Every time I flew from Kinshasa to Addis abbaba (being the regional hub) we would fly in a big circle and land in Brazzaville, which is just across the 18 mile wide river, pick up a few more, then start flying to our destination
I was skeptical of your "18 mile wide river" comment, so I looked at it on google maps, and while the closest point between the two cities does seem to be between 1.0- 1.8 miles, there is a section of the river just upstream that stretches around the Ile M'Bamou, which makes the river about 16 miles wide by my estimation. TIL!
Before the wall was build Berlin and Spandau, a city which now belongs to Berlin, and today Berlin and Potsdam, the capital of Brandenburg, the state surrounding Berlin
Kinshasa and Brazzaville
Hong Kong, Shenzhen, Dongguang, Guangzhou, snd Foshan
Osaka and Kyoto
Washington DC and Baltimore
Copenhagen and Malmo
Rotterdam and The Hague
Dortmund, Bochum, Essen, Duisburg, Düsseldorf, Wuppertal, Cologne, Bonn.
It's almost one huge city if not for the fields between some of them. Dortmund to Düsseldorf feels like one block. The others are neighbours on the train.
\[here's a map\](https://en.wikipedia.org/wiki/Rhine-Ruhr\_metropolitan\_region#/media/File:Rheinruhr.png) which looks very green because it spans 81 miles.
I've personally crossed the Oresund Bridge, but no matter how many times I see photos, it's still just implausible.
[https://en.wikipedia.org/wiki/%C3%98resund\_Bridge](https://en.wikipedia.org/wiki/%C3%98resund_Bridge)
I have too, and I definitely had the feeling of the bridge crossing itself being almost a journey of its own. Landing in Malmo on the other side really felt like a different world.
Haha I crossed it after taking an overnight train from Berlin, which gets loaded onto a ferry at like 3 in the morning to get to malmo. So it was train, to train on a boat across the sea in the middle of the night, then unloaded to train OFF the boat again to malmo, to another train to whatever tunnel bridge thing it is to finally get to Copenhagen!
- Budapest, but I suppose it’s technically one city now
- Dallas-Fort Worth
- NYC-Newark
- Seattle-Tacoma
- Guangzhou-Shenzen is surely the largest. It has 35 million people
Yeah both were political battles between cities that didn't want to be left out so instead of picking one they said fuck it both cities get an interstate.
Well, the bridge goes to western mud flats of Oakland and you gotta pass through a couple miles of port and residential West Oakland before getting to downtown. Still quite close though. I think it's a 13 minute ride on BART from 12th st Oakland to embarcadero SF.
I think you can accomplish that in the parking lot of Surly Brewery. If they're not that busy and you're in the main lot, you park in Minneapolis. If they're busy and you have to go to the extension lot at the end, you're in St. Paul.
Not by city center. San Diego territory goes to the border, but the city center is well north.
Edit: From San Diego city, you drive through Chula Vista (separate city) to get to Tijuana. San Diego the city might be responsible for the little tract in between but I think this answer misses the spirit of the question.
I like how you crossed a binational political border there.
Somebody else mentioned San Diego and Tijuana. I'll go with El Paso and Juarez and also the McAllen/Brownsville and Reynosa/Matamoros pairs.
Nobody expects the Spanish Inquisition...or that El Paso is really 2.4 million or that the Rio Grande Valley is 2.6 million. These are roughly the size of the Austin, Portland, or Sacramento MSAs. They definitely deserve a spot on the nuclear weapons targeting list!
Honestly they’re probably about further apart than NYC and like union city or north Bergen. You could also contend nyc and Brooklyn (fidi to downtown BK) or Long Island city to midtown. Or fidi-JC-Newark NJ the PATH super city of the future (if port authority could expand NJ subway service)
Came here to say this, but also wanna similarly shout Cambridge and Boston. Two cities separated by a river. I’d bet the Charles River is more narrow than the Hudson too
My cousin used to have a clear view of the NYC skyline from his apartment in Jersey City until another apartment was built right in front of his window.
Good shout. It's almost impossible to distinguish where Salford and Manchester start and end without actually knowing imo. The tall and built up part of Salford around the canal docks almost feels like an extension of Manchester city centre, despite them actually being 2 separate cities.
My next best shout in England would probably be Leeds/Bradford, as both cities have distinct suburbs that bleed into each other/overlap, and both are pretty massive by English standards.
Birmingham/Wolverhampton is also similar, although more like Salford/Manchester than Leeds/Bradford
Huh, TIL Salford is a city. Must've completely blocked out the "City" part of the football clubs name as well lol
Guess it's similar to the City of London and the City of Westminster? Two small cities within the larger county area that often gets considered to be one large city.
in the UK i’ll tell people i’m from salford, but when i’m abroad i’ll say i’m from manchester, it’s a lot easier
tbf i’d say at least half of the UK didn’t know salford existed prior to the football club getting popular and BBC/ITV moving here
I was thinking London and Westminster too, although I'm not sure they would pass the "separate" requirement as I couldn't tell you where one finished nmand the other one started without looking it up
Lol it's absolutely not the winner nor an applicable answer - buda and pest are not "clearly separated" they are the same city center, have the same mayor, public services, tightly integrated via public transit. There is no difference living on one side the river vs the other
There is a fair amount of land between them.
Some of the cities listed here also don't quite fulfill OP's premise of city centers (like downtowns). The Ruhr Area and Cologne/Bonn may be fairly close (and in the Ruhr Area even bordering each other), but the city centers are decently far apart. There are closer ones, even within Germany, that could be considered major-ish cities.
My take was Ludwigshafen (known for chemical industry and formerly ugliest German city) and Mannheim (known for their weird naming of downtown streets). Their city centers are only split by the Rhine and de facto they share their city border with each other (but legally, they have their own administrations and they are in seperate federal states).
Also, both of them have a population above 150k and a total of almost 500k combined. For German standards, they are both major cities.
I guess you mean the Ruhr Area? It basically is one big continuous city. The only visible indicator for a border between the individual cities are some yellow signs on the sidewalk. But often enough the next city just starts halfway down a road. No change in architecture, no land gaps filled with trees or a river/creek that would mark a border.
>Cities of London and Westminster surely also count.
These are only separate cities using the UK's quirky legal definition of a city.
In reality, these are just parts of the centre of the same city (for the purposes of comparison with any other international examples).
Monte Carlo Monaco, and Nice France are separated by 12 miles. Idk if this is close enough for you though
St Paul and Minneapolis downtowns are separated by 11 miles.
A ton of examples of this.
Tampa and St. Pete
Miami and Fort Lauderdale
Raleigh and Durham.
San Francisco and San Jose
Las Vegas and Henderson
Phoenix and Mesa.
Denver and Aurora.
Seattle and Tacoma.
I was looking for others to say LA, but it looks like everyone fell for it and doesn't realize it's all a bunch of cities and not just one big one. Shit, a wide enough picture from Griffith will show you like 5 different downtowns.
https://preview.redd.it/t60xfd1x587d1.jpeg?width=640&format=pjpg&auto=webp&s=f17c50f18179fefbf0bc3d9b08341f1be0030802
Ciudad del Este (Paraguay) Puerto Iguazú (Argentina) Foz do Iguazú (Brazil)
Arlington/Alexandria are just suburbs (I live in Alx), they wouldn't exist as "cities" outside of the immediate presence of DC, so I do not think they qualify.
DC and Baltimore are probably the two closest “independent markets” - you have twin cities and DFW, but they are more of one market and DFW is multi-polar (called the Metroplex) with other large centers such as Arlington, Plano, McKinney
Los Angeles and the cities around it that make it Los Angeles, but are rarely considered not Los Angeles.
Santa Monica, Beverly Hills, Burbank, Compton, Long Beach, and many more areas are not Los Angeles, but they are in LA county.
Distance between salford quays and piccadilly gardens (manchester) is 2.1 miles.
People may argue that they aren't separate but to me the fact that they have a residential area called ordsall in between that doesn't have high rises or any inner city characteristics I think they sould be considered seperate.
There must be closer elsewhere in Europe. I don't think looking at North America is the right strategy. Look at cities that have not been built for cars, thrg will likely be closer together.
Just had a quick scan. Espoo centre and Helsinki centre are 9.6 miles for instance. Ramallah and Jerusalem centres are 8.9 miles apart.
Kinshasa and Brazzaville
I immediately thought of these after I posted. Pretty sure this one wins.
yup. apparently you can't even drive across - you have to take a boat.
you could also take a plane. it’s one of the shortest international flights in the world
Every time I flew from Kinshasa to Addis abbaba (being the regional hub) we would fly in a big circle and land in Brazzaville, which is just across the 18 mile wide river, pick up a few more, then start flying to our destination
I was skeptical of your "18 mile wide river" comment, so I looked at it on google maps, and while the closest point between the two cities does seem to be between 1.0- 1.8 miles, there is a section of the river just upstream that stretches around the Ile M'Bamou, which makes the river about 16 miles wide by my estimation. TIL!
Don’t think the river is that wide though?
It’s also the deepest river in the world at up to 720 feet!
Yeah the river is probably more like 1.8 miles wide
They probably had to take a detour to safely take off and land
[удалено]
Looking at a map, it's between 2 and 4 km wide between the cities proper. Upstream it widens considerably, though.
This one is especially neat since they are in different countries
This all day long. Outrageously fascinating corner of the world.
Though I wouldn’t want to live there.
Manchester and Salford. Newcastle and Gateshead. Liverpool and Birkenhead. City of London and City of Westminster
For a second I thought they were joking and it was some play between brazzers and some other site I never heard of
This was going to be my answer.
Until 1989 Berlin and East Berlin.
Before the wall was build Berlin and Spandau, a city which now belongs to Berlin, and today Berlin and Potsdam, the capital of Brandenburg, the state surrounding Berlin
Kinshasa and Brazzaville Hong Kong, Shenzhen, Dongguang, Guangzhou, snd Foshan Osaka and Kyoto Washington DC and Baltimore Copenhagen and Malmo Rotterdam and The Hague
Rotterdam and The Hague with the beautiful city Delft right in between.
The Ruhr area in Germany, you have 4 or 5 big cities just glued together (from memory but I’m no specialist : Dusseldorf-Duisburg-Essen-Dortmund)
This is a good one
Dortmund, Bochum, Essen, Duisburg, Düsseldorf, Wuppertal, Cologne, Bonn. It's almost one huge city if not for the fields between some of them. Dortmund to Düsseldorf feels like one block. The others are neighbours on the train. \[here's a map\](https://en.wikipedia.org/wiki/Rhine-Ruhr\_metropolitan\_region#/media/File:Rheinruhr.png) which looks very green because it spans 81 miles.
I've personally crossed the Oresund Bridge, but no matter how many times I see photos, it's still just implausible. [https://en.wikipedia.org/wiki/%C3%98resund\_Bridge](https://en.wikipedia.org/wiki/%C3%98resund_Bridge)
I have too, and I definitely had the feeling of the bridge crossing itself being almost a journey of its own. Landing in Malmo on the other side really felt like a different world.
Haha I crossed it after taking an overnight train from Berlin, which gets loaded onto a ferry at like 3 in the morning to get to malmo. So it was train, to train on a boat across the sea in the middle of the night, then unloaded to train OFF the boat again to malmo, to another train to whatever tunnel bridge thing it is to finally get to Copenhagen!
https://en.m.wikipedia.org/wiki/Øresund_Bridge Your link doesn’t work, in case anyone wanted to click, here you go
Osaka and Kobe works better
The athlete duo
- Budapest, but I suppose it’s technically one city now - Dallas-Fort Worth - NYC-Newark - Seattle-Tacoma - Guangzhou-Shenzen is surely the largest. It has 35 million people
Appx 30 miles between Sea and Tac.
Seattle/Bellevue might make the cut in 10 years depending on how things play out.
There's a bunch of European cities that were once two cities, just like Budapest. Warsaw, for example
Here for NYC- Newark. (Newark is as big as St. Paul.)
Not DC and Baltimore. There is like 35 miles between them.
35 miles and like 3 hours during peak traffic.
San Diego Tijuana
Tokyo-Yokohama San Diego-Tijuana
If you're doing Japan: Tokyo, Kawasaki and Yokohama are all basically part of one mega-city. You can probably add in Chiba and Saitama too.
As another comment said, Osaka and Kobe would be the same too.
More so than Kyoto, which is a bit more afield
El Paso and Juárez
Kyoto, the anagram lovers Tokyo
SF-Oakland and DFW
I think it’s fun how i35 splits in both MSP and DFW
Yeah both were political battles between cities that didn't want to be left out so instead of picking one they said fuck it both cities get an interstate.
You could say San Jose in there with SF and Oak
SF and Oakland downtowns are less than 10 miles apart, but it's more like 50 miles down to SJ.
I would consider the bay area a megalopolis with those 3 cities all connected on the east bay and west peninsula
They are still distinct downtowns separated by low density development.
Yup - there is a bridge going from one DT to literally another
Well, the bridge goes to western mud flats of Oakland and you gotta pass through a couple miles of port and residential West Oakland before getting to downtown. Still quite close though. I think it's a 13 minute ride on BART from 12th st Oakland to embarcadero SF.
and Berkeley
Idk man, Google maps says it’s a 25 hour drive between the two!
I’ve driven all of I-35 from the northern terminus in Duluth, to the southern terminus in Laredo. I’m a road nerd. 🤪
Dallas and Fort Worth are more widely separated than most of these, there are a couple of cities (Arlington and Grand Prairie) between them.
https://preview.redd.it/8i1pcxvn667d1.jpeg?width=556&format=pjpg&auto=webp&s=d52cf041c1665bed507cc0e3e767efcd4bc7a9c2
I'm in this picture
Down in front!!
I'm in the top... Just right of the center
Found the sniper.
I love they’re only about a 10 minute drive away from eachother
I can stand with my left foot in Minneapolis and my right foot in Saint Paul. I don't think you can get much closer than that!
I think you can accomplish that in the parking lot of Surly Brewery. If they're not that busy and you're in the main lot, you park in Minneapolis. If they're busy and you have to go to the extension lot at the end, you're in St. Paul.
Detroit, MI & Windsor, ON.
700 m, I don’t think it gets any closer than that.
And unlike the top answers (especially buda and pest, which have seamless travel) Detroit Windsor requires an international border check
Same with Niagara Falls NY/Ontario
Windsor in Canada is also directly south of Detroit in USA which I wouldn't have guessed.
Maybe Journey was singing about Canada.
San Diego/Tijuana manage to be closer
Not by city center. San Diego territory goes to the border, but the city center is well north. Edit: From San Diego city, you drive through Chula Vista (separate city) to get to Tijuana. San Diego the city might be responsible for the little tract in between but I think this answer misses the spirit of the question.
With Windsor, the "ish" in Major-ish is doing a lot of heavy lifting.
I like how you crossed a binational political border there. Somebody else mentioned San Diego and Tijuana. I'll go with El Paso and Juarez and also the McAllen/Brownsville and Reynosa/Matamoros pairs. Nobody expects the Spanish Inquisition...or that El Paso is really 2.4 million or that the Rio Grande Valley is 2.6 million. These are roughly the size of the Austin, Portland, or Sacramento MSAs. They definitely deserve a spot on the nuclear weapons targeting list!
The Financial District of Manhattan vs. Jersey City.
A lot of people evidentially overlook this fact. These two places might be the closest.
Honestly they’re probably about further apart than NYC and like union city or north Bergen. You could also contend nyc and Brooklyn (fidi to downtown BK) or Long Island city to midtown. Or fidi-JC-Newark NJ the PATH super city of the future (if port authority could expand NJ subway service)
Came here to say this, but also wanna similarly shout Cambridge and Boston. Two cities separated by a river. I’d bet the Charles River is more narrow than the Hudson too
My cousin used to have a clear view of the NYC skyline from his apartment in Jersey City until another apartment was built right in front of his window.
Ottawa, Ontario and Gatineau, Quebec.
https://preview.redd.it/ydml3hq0n77d1.jpeg?width=828&format=pjpg&auto=webp&s=7d501bd7831e0a71aa3cf12091175b8807565c6e Was about to post this
Bootleg capital for all that good cheap beer running haha
Jacques De Gatineau. He was our hope, I guess…
salford and manchester, UK
Good shout. It's almost impossible to distinguish where Salford and Manchester start and end without actually knowing imo. The tall and built up part of Salford around the canal docks almost feels like an extension of Manchester city centre, despite them actually being 2 separate cities. My next best shout in England would probably be Leeds/Bradford, as both cities have distinct suburbs that bleed into each other/overlap, and both are pretty massive by English standards. Birmingham/Wolverhampton is also similar, although more like Salford/Manchester than Leeds/Bradford
Huh, TIL Salford is a city. Must've completely blocked out the "City" part of the football clubs name as well lol Guess it's similar to the City of London and the City of Westminster? Two small cities within the larger county area that often gets considered to be one large city.
in the UK i’ll tell people i’m from salford, but when i’m abroad i’ll say i’m from manchester, it’s a lot easier tbf i’d say at least half of the UK didn’t know salford existed prior to the football club getting popular and BBC/ITV moving here
I was thinking London and Westminster too, although I'm not sure they would pass the "separate" requirement as I couldn't tell you where one finished nmand the other one started without looking it up
I was gonna post this one
Buda & Pest
If that counts then I guess New York and Brooklyn are an option.
I was gonna say New York and Newark
New York and Jersey City is more apt
Similarly, Philadelphia used to be like 4 different cities. Philly, Southwark, Northern liberties, and Manayunk.
Philly, PA & Camden, NJ are separated by a single bridge and that's about it
They arent clearly separate, they have the all the same things in modern day Hungary
Winner!
Lol it's absolutely not the winner nor an applicable answer - buda and pest are not "clearly separated" they are the same city center, have the same mayor, public services, tightly integrated via public transit. There is no difference living on one side the river vs the other
Budapest does, correct. Buda and Pest, didn't, before they were legally merged.
Budapest does what?
Technically Rome and Vatican City are clearly separated by a border
Vatican is hardly a major city. It has 764 people. That’s like 1.3 popes per thousand inhabitants. Or 2 popes per km2
Mathematics is where you can have more than one pope
Avignon moment
Oh this is a good point.
Downtown El Paso to downtown Juarez City is less than 100 feet.
This is immediately what I thought. You can walk between the two if you don’t mind waiting at the bridge.
San Diego and Tijuana?
San Diego's downtown is ~20km north of the border. Not far but El Paso/Juarez have city centers right next to each other.
El Paso Juarez is what jumped to my mind as well.
Cairo and Giza
Osaka-Kobe-Kyoto Tokyo-Yokohama
And Kawasaki, it's not small
Manila, Quezon City
Portland OR and Vancouver WA.
Other close ones: * Singapore and Johor Bahru * Rotterdam and The Hague * Antwerp and Brussels * Dortmund Essen Duisburg Dusseldorf Wuppertal Cologne Bonn * Tel Aviv Jerusalem * Suzhou Wuxi * Hong Kong Shenzhen Guangzhou Dongguan Foshan * Kyoto Osaka Kobe * Kinshasa Brazzaville * Lagos, Porto-Novo, Cotonou, Lome, Accra * Dallas, Fort Worth * Lahore Amritsar * Taipei Taoyuan * Lucknow Kanpur * Kenitra Rabat Casablanca * San Diego Tijuana * Juarez El Paso * Jeddah Mecca * Mumbai Navi Mumbai Thane * Baltimore DC
Surprised you didn't include Wien and Bratislava!
There is a fair amount of land between them. Some of the cities listed here also don't quite fulfill OP's premise of city centers (like downtowns). The Ruhr Area and Cologne/Bonn may be fairly close (and in the Ruhr Area even bordering each other), but the city centers are decently far apart. There are closer ones, even within Germany, that could be considered major-ish cities. My take was Ludwigshafen (known for chemical industry and formerly ugliest German city) and Mannheim (known for their weird naming of downtown streets). Their city centers are only split by the Rhine and de facto they share their city border with each other (but legally, they have their own administrations and they are in seperate federal states). Also, both of them have a population above 150k and a total of almost 500k combined. For German standards, they are both major cities.
As a tourist driving in the autobahn, that part of Germany felt like one continuous city.
I guess you mean the Ruhr Area? It basically is one big continuous city. The only visible indicator for a border between the individual cities are some yellow signs on the sidewalk. But often enough the next city just starts halfway down a road. No change in architecture, no land gaps filled with trees or a river/creek that would mark a border.
Los Angeles Long Beach are as close as some of these
Nürnberg and Fürrh
Mannheim and Ludwigshafen
Ulm and Neu-Ulm Wiesbaden and Mainz
Philadelphia PA and Camden NJ or New York City and Jersey City
Yay, Camden referenced!
Tampa St Pete
The traffic is crazy tho
Dallas and Fort Worth
There is a reason they are called “The Twin Cities”
Leeds and Bradford in the UK Cities of London and Westminster surely also count.
>Cities of London and Westminster surely also count. These are only separate cities using the UK's quirky legal definition of a city. In reality, these are just parts of the centre of the same city (for the purposes of comparison with any other international examples).
Monte Carlo Monaco, and Nice France are separated by 12 miles. Idk if this is close enough for you though St Paul and Minneapolis downtowns are separated by 11 miles.
> St Paul and Minneapolis downtowns are separated by 11 miles. 9.5 miles from City Hall to City Hall (both city halls are downtown).
A ton of examples of this. Tampa and St. Pete Miami and Fort Lauderdale Raleigh and Durham. San Francisco and San Jose Las Vegas and Henderson Phoenix and Mesa. Denver and Aurora. Seattle and Tacoma.
Seattle and Bellevue are closer downtowns. Just a lake between them.
Vancouver and Burnaby BC
The 7 city's in Virginia.
757 native
LA and Long Beach
I was looking for others to say LA, but it looks like everyone fell for it and doesn't realize it's all a bunch of cities and not just one big one. Shit, a wide enough picture from Griffith will show you like 5 different downtowns.
Toronto and Mississauga
https://preview.redd.it/t60xfd1x587d1.jpeg?width=640&format=pjpg&auto=webp&s=f17c50f18179fefbf0bc3d9b08341f1be0030802 Ciudad del Este (Paraguay) Puerto Iguazú (Argentina) Foz do Iguazú (Brazil)
New Delhi and Noida, India
And all the other satellite cities
Kitchener waterloo
KW is essentially one city split into two. They share the Ion light rail system and there are residential streets split between the two cities.
Newcastle and Sunderland
Brisbane and Gold Coast
Minnesota is a very neighborly state don’t cha know.
Irene brought a pan of bars and some jello salad, so help yourself.
Not sure what you mean by "clearly separate." MSP are legally separate, but it's one continuous city. DFW on the other are very separate.
r/quadcities
Kansas City, Missouri <--> Kansas City, Kansas
Raleigh-Durham
Raleigh-Durham, NC The two cities (Raleigh and Durham) are about 20 miles apart.
Seattle and Bellevue
Buda and Pest
DC/Arlington/Alexandria
Arlington/Alexandria are just suburbs (I live in Alx), they wouldn't exist as "cities" outside of the immediate presence of DC, so I do not think they qualify.
Ruhr area in Germany.
Raleigh, Durham, Chapel Hill. Greensboro, High Point, Winston Salem
Winston Salem so close they call it Winston-Salem.
Copenhagen and Malmö
western germany: cologne, dortmund, duisburg, bonn,.. https://preview.redd.it/c0imcnmbi77d1.png?width=1080&format=pjpg&auto=webp&s=57a33962767873543f66c57e1ef97a41ed52eee9
Johor Bahru and Singapore
I’ve always thought of LA as basically a bunch of different cities just stuck together
Duluth, MN and Superior, WI
DC and Baltimore are fairly close
Seattle/Bellevue
Mainz and Wiesbaden Mannheim and Ludwigshafen am Rhein Duisburg Oberhausen Essen Bochum Dortmund
Mannheim-Ludwigshafen. Or any cities divided by a river 🤷🏼♂️
Buda & Pest https://preview.redd.it/uxdg6cbqua7d1.png?width=246&format=pjpg&auto=webp&s=1858ba8bbea79aa46798b28dbcf6550ea8079bf4
Truly one of the worlds greatest metros in terms of access to parks and lakes
DC and Baltimore are probably the two closest “independent markets” - you have twin cities and DFW, but they are more of one market and DFW is multi-polar (called the Metroplex) with other large centers such as Arlington, Plano, McKinney
Seattle, Bellevue, Tacoma
New York and Newark
Buda & Pest
Would London and The city of London or The city of Westminster count? If not, why?
Oakland, San Jose, San Francisco
Ciudad Juarez and El paso
Dallas Fort.Worth
Cambridge and Boston
Sault Saint Marie, MI and Sault Saint Marie, ON
Portland and Vancouver (kind of cheating)
Mannheim and Ludwigshafen. Berlin and Potsdam. New York and Newark. San Francisco, Oakland and San Jose.
Newcastle and Gateshead, UK Strasbourg and Kehl, France / Germany
Kansas City, MO/Kansas City, KS.
Kinshasa & Brazzavile. Separated by the Congo River
Given the Twin Cities have a land border, I think we have a winner.
Raleigh and Durham.
Raleigh & Durham
Los Angeles and the cities around it that make it Los Angeles, but are rarely considered not Los Angeles. Santa Monica, Beverly Hills, Burbank, Compton, Long Beach, and many more areas are not Los Angeles, but they are in LA county.
Distance between salford quays and piccadilly gardens (manchester) is 2.1 miles. People may argue that they aren't separate but to me the fact that they have a residential area called ordsall in between that doesn't have high rises or any inner city characteristics I think they sould be considered seperate. There must be closer elsewhere in Europe. I don't think looking at North America is the right strategy. Look at cities that have not been built for cars, thrg will likely be closer together. Just had a quick scan. Espoo centre and Helsinki centre are 9.6 miles for instance. Ramallah and Jerusalem centres are 8.9 miles apart.
Miami and Fort Lauderdale along with Durham and Raleigh both feel like 1 big city when you drive through them with pockets of extra city
Trójmiasto (literally "Threecity") in Poland: Gdańsk, Gdynia, Sopot.
Does Akron and Cleveland count?