This all became a bit too interesting for me and I lost a few more hours than I intended to. Here's where the four 20,000+ San Francisco squares are, followed by all the New York ones. That's just the way grids and numbers work, of course. With my favoured grid, San Francisco ends up with 4 grid squares over 20,000 but with the shifted grid we get a higher maximum density value in one grid square but only 3 squares over 20,000. We get a higher value in this San Francisco squareīut we get a lower figure for max density in New York The top 36 squares are all in New York, but then we have a higher density square in San Francisco, because we moved the grid - now we get over 30,000 and if we keep shifting the grid we could get even higher - but of course that's not the method I'm using here, it's all about comparing things nationally on a like-for-like basis. But the overall story of density doesn't really change and still goes New York, New York, New York, etc. The maximum in New York comes out lower, San Francisco comes out higher and a few other places are a bit different, as we might expect. Instead of 161 squares with 20,000 or more, I got 160 and basically all in the same locations. Hmm, but what kind of result do you get if you shift the grid around a bit? This is the question all the methods nerds want to know, and of course I do too so I also did this with another slightly different grid - for the lower 48 states only. Once again, I made all the maps using QGIS and automated the production of the individual files using the QGIS Atlas tool within QGIS.Īlternative grids - higher/lower max values? There's a video file of this in the web folder, plus a slower version.
The most densely populated square km in each state (based on my 1km grid) Such an approach is not, of course, a uniformly gridded approach to understanding population density but it is quite good fun! We'll still end up with the same answers in relation to where is 'most densely populated' but we'll get different numbers. If we just want to find a single cell with a higher population then we can of course do this without too much trouble. Possibly my favourite approach to this is by the WorldPop project, although there are many other sources (see below). The approach of using a continuous grid over a whole country - or indeed the whole world - is pretty common these days and helps us compare areas on a like-for-like basis. This is a more conservative approach than if I'd use an intersect approach but I wanted to remain on the cautious side. Just remember a few things as you read through this piece: a) moving the grid around will of course get you different results, but this is the same with all gridded population data - though mostly the results only change a bit - even so, grids are still useful b) the populations are calculated using groups of census blocks, which don't align perfectly with the squares - that's why it says 'approximate population' on the images, and that's also why I used a blurred focal area around the squares, a nod to the fuzziness of things c) this is US Census data from 2020, so it's about the best and most recent data there is and d) my numbers are likely an underestimate because I chose to assign only those census blocks to each 1km square where the centroid falls within the square. Yes, there appears to be an 'odd one out' here This is what it looks like when you put them on a map. The top 65 most dense 1km squares are all in New York. This is basically population density central for the US The most densely populated area in the United States You can find high resolution versions of the maps below in this web folder. The highest density in the UK is about 25,000 in a single square km (in east London). Bear in mind that the highest value I found in Europe was just under 53,000 in the Barcelona metropolitan area (L'Hospitalet de Llobregat, to be more precise). Based on my US-wide 1km x 1km grid, here is the maximum 1km cell population in the US, followed by maps for every state. If you want to know whether anywhere in the United States is as densely populated as in Europe then read on, but the answer is: yes, New York City has higher densities than Europe, and a few other spots have European-level densities - but not very many. If you're looking for more on methodology and data sources, scroll to the bottom of the page. I also attempt to find the most densely populated square kilometre in each state. This is not a surprise, so in this long and slightly messy post I'll say a bit more about my attempts to calculate exactly where it is and how many people live there, using US Census 2020 data and a similar method to my previous post on the most densely populated square km of the United Kingdom. The most densely populated square kilometre in the United States is on the Upper East Side in New York City.