I really dont think cities have an upper limit. From an urban geography question people tend to live within 40 minutes travel time of work. Weather thats walking, driving or train, 40 minutes is the rough commute tolerance for most people.

Of course you have multiple employment nodes in modern cities which means they can sprawl much broader and what you get now are interconnected urban regions.

If you explained how massive cities are today to somebody from 500 years ago they would think you were raving mad. Even the largest most epic cities of the ancient world would be a small to medium sized city today.

As technology allows for more density, more livability with more people in a common area in terms of population I really don't think there is an upper limit of population Geographic lateral sprawl is probably the only factor that will continue to be limiting.

If that's the case, what's the distinction you're trying to make between London or Chicago? I'm pretty sure they restaurants chains on the Loop might choose to open a new unit on the Northern Lake.

Shoreditch and Soho are both inside Inner London: https://en.wikipedia.org/wiki/Inner_London . All important job nodes, big terminal stations of the city, are all inside Inner London. Hence, for the purpose of this thread, London is a "city", a "mononuclear city", as everything is inside its very core that's been called "London" for two millenia.

It's a matter of definition. You are looking into individual buildings or city blocks; I'm looking into regions.

Either way, this thread is about how big cities like London, Tokyo or Chicago can grow, and NOT on how large Pearl River Delta or Yangtze River Delta or Rhine-Ruhr or São Paulo Macrometropolis can grow.

In other words, can New Delhi or Kinshasa or Lagos reach 100 million people or that's a too big number to make them viable? Or Los Angeles stopped growing because it reached a critical size that doesn't allow it to grow much more; or did it stop for other reasons and could very well go for 30 million undisturbed?

No, all of this is wrong.

I’m not talking about chains, I’m talking about successful trendy restaurants that people in the east or west would want to go to but don’t because it’s not their entertainment district.

The analogy would be a restaurant in the West Loop opening another location in River North. But they don’t do this, because those are part of the same CBD. Soho and Shoreditch are NOT no matter how many times you claim they are both part of “Inner London”. They are different parts of the city, accessed from different commuter train stations, and it’s a pain in the ass to get from one to the other.

Have you ever even been to London? Because you seem to be completely ignorant of how locals think about and live in the city.

There is no “Tokyo, London or Chicago” discussion because Chicago has a totally different urban topography from Tokyo or London. Chicago is monocentric, and London and Tokyo are polycentric.

To answer the original intent of the question, it depends on how far out you have to go before people stop associating with the primary city.

With a monocentric city model, there are hard limits, although almost no city of any size is totally monocentric. The most monocentric city I can think of is Calgary, Alberta, which is not particularly big. Chicago is quite monocentric for a city of its size.

Most metros are on a sliding scale between polycentric rail-based models (Tokyo) or dispersed auto-based models (Phoenix). In the former, I think you can add population indefinitely as long as you keep adding nodes and you offer more express types of rail services between nodes.

In the latter, I think you can add population indefinitely as long as people only do all their activities within their part of the region and don't do 3 hour-long 150 mile commutes to the other side.

I think one of the big limiters in both places are accessing amenities where only one of them is required in the whole metro, but everyone has to use it from time to time. A major international airport - like the kind that's a major hub where you can fly anywhere, and not an airport for charter airlines or low cost carriers - is a perfect example. LA only needs one: LAX. If you live in Moreno valley and need to fly to Tokyo, you are fighting traffic for 2 hours to get to the only airport that has flights to Tokyo. Similarly, if you're on the edge of the Kanto region and you need to fly to LA, you're sitting on three different trains for 2 hours to either reach Narita or Haneda.

Look, it’s pretty simple.

An actually monocentric city (like Chicago) is limited by the fact that, at some point, people on its periphery can’t actually access the amenities and jobs in the core (because travel/commute times are too long), and there ceases to be any benefit of living there instead of just moving to a smaller city.

In a polycentric city, like LA or London or Tokyo, the suburbs can spread way father because “going into town” can mean going to West LA or Downtown LA or Long Beach, or to the West End or the City/Shoreditch, or to Yokohama or Toshima or Ueno, etc.

Someone in Surrey can take a train into Victoria Station and then get to work in Marylebone or Mayfair, shop in Oxford Street, go out to great restaurants etc. And someone in Essex can take a train into Liverpool Street Station and go to work in the City, go out in Shoreditch, etc. That effectively extends the potential reach of how geographically large the city can be.

Multiple airports probably makes more of a difference than multiple historic cities, too.

My point is that there really aren't any true monocentric cities. Downtown Chicago has 600,000 jobs. That's what? 10% of all the jobs in Chicagoland?

I agree that a hypothetical monocentric city reaches hard limits in terms of how far it could grow - that's actually why there are no monocentric cities.

Seems like most of the 'action' in Chicago is still either the Loop or the Near Northside.

The high-profile high-paying office employment is indeed concentrated in the Loop. But there’s also lots of manufacturing and logistics and backend offices that are in the suburbs.

O’Hare and Midway on their own could sustain a smaller metro.

https://pbs.twimg.com/media/FAVs1rqXsAEgtdE.jpg
https://twitter.com/danielkayhertz/s...253644804?s=21

^ Evanston surprises me a bit because it's not really a major office center, but I guess the university and 2 hospitals put up a decent # of jobs.

Enough to rank in the top 25 zip codes at least. But if the Loop were to actually hit its theoretical limits, then Evanston or Rosemont or Schaumburg would become reasonable secondary nodes.

Chicago is an unusually monocentric city, not because it’s unable to create other employment nodes (Just some new transit lines and corporate investment would suffice, rather the city has never felt the need for a competing CBD. The boundaries wander around -further North, further West, further South, but the office limits are very very far off considering how many of the CTA lines are not at capacity.

NYC’s multiple CBDs are just an accident of history and geography. The ports concentrated wealth in the FiDi, then the subways concentrated wealth in Midtown, and bridge congestion makes Brooklyn and Jersey City useful nodes.

From the times I have been to Chicago, I couldn't help notice the vast majority of large buildings were concentrated in the Loop and then up Michigan Ave tapering off around Lincoln Park and then again in Evanston which has a pretty respectable skyline. Contrast to here in Houston where they just stick a massive tower anywhere...

Can any large metro really be Monocentric?

I cant think of any major MSA that doesn't have multiple nodes of employment/density.

Even smaller metros of 1 million or less usually have a downtown, then maybe a secondary office area, an entertainment district, a University area or airport manufacturing/logistics area etc.

Chicago is abnormally monocentric for a very large city because of when and how it developed. It was the original city built around rail terminuses to bring people into the CBD from far and wide. In cities like London or even New York, these were added later (and London’s are still all on its historic periphery). Chicago was basically built over its (very centralised) rail network, not the other way around.

The CTA and Metra don’t even have lines that don’t go downtown.

This is how you get a monocentric city:

https://i0.wp.com/transitmap.net/wp-...2%2C1200&ssl=1

There are other monocentric cities in the US, but I can’t think of any nearly as large as Chicago.

^ Good point. I think Clark & Lake covers almost every CTA line if I recall.

This for comparison is the equivalent map for London, showing tube and overground lines, as well as National Rail (which people use to commute as far as the periphery of central London). Do we see a difference?

https://londonmap360.com/carte/image...-train-map.jpg

Note: I can’t seem to embed an image that isn’t enormous, but the link goes straight to the photo.

Chicago's string of lakefront residential highrises extends WAY north of Lincoln Park. My mom and dad live in a 513' tall lakefront highrise all the way up in Edgewater, 7 miles north of the loop. The big black Miesian building in the middle:

https://cdngeneral.rentcafe.com//dms...af28d450a9.jpg
Source: https://www.flatslife.com/blog/2019/...neighborhoods/





And Evanston might have a "respectable" skyline by suburban chicagoland's pathetic standards, but it's relatively small potatoes in the grand scheme of things, and mainly consists of residential highrises. The tallest building is 275' , and there are maybe 2 dozen buildings over 10 stories. It's nice and cohesively urban, but it's nothing all that remarkable in the height department.

https://www.cityofevanston.org/home/...33829034770000
Source: https://www.cityofevanston.org/gover...al-report-2020

Evanston also has only around 80,000 people and is a suburb. It might not have much in the way in height but still punches well above its weight, imo. We have one suburb with any significant skyline but it's about 1.5x the size and about a third as many buildings 'downtown'; it's technically unincorporated.

The Lakefront skyline is impressive, but it’s got nothing to do with whether Chicago is a monocentric or polycentric city. Those are all residential towers. It’s not as if Lakeview or Edgewater are an additional commercial hub in the way that DT Brooklyn or even Long Island City are.

Of the big three Canadian cities, Montreal is, by quite a large measure, the most monocentric. Most of the tall buildings, residential and office, are found in the core, notwithstanding a handful of very small dispersed urban nodes. Toronto has a massive CBD but many, many dispersed urban nodes that are really quite large. Vancouver is proportionately, the most polycentric, as it has the dispersion of large nodes like Toronto, but with a proportionately much smaller CBD.

The Rhine-Ruhr area is a very polycentric but nonetheless highly integrated labour market with several million daily commuters. Of course people live in Duisburg and commute to work in Dusseldorf or Essen.

As of 2020, 315,000 workers commuted into Dusseldorf while 105,000 commuted out of the city, with Duisburg and Cologne being the top 2 sources.

Some 105,000 commuted out of Duisburg (with Dusseldorf and Essen being the top 2 destinations) and an equal number commuted into the city.

Around 335,000 workers commuted into Cologne, 161,000 commuted out of the city; around 160,000 commuted into Essen and 105,000 commuted out of the city (with Dusseldorf being the top destination).

Just for the sake of a rough comparison: in 2010, 265,000 workers commuted into San Francisco and 101,000 commuted out of the city; 119,000 commuted into Oakland and 100,000 commuted out of the city; 155,000 commuted into San Jose and 205,000 people commuted out of the city. Numbers will have increased quite a bit, but it's pretty clear we're not talking about a completely different ballpark.

Does that make Rhine-Ruhr a 'city'? No, just as the Bay Area, Washington-Baltimore, the Greater Boston Area aren't 'cities' either. The truth is that metro areas are just that - they were never meant to represent cities. Sometimes they might overlap, but the more an urban area expands and the more polycentric it becomes, the less likely that is to be the case.