My adventures in population density continue - this time I try to find the maximum population density in the United States, using 2020 Census data - e.g. here's the maximum 1km square I found in each state long read here:

using a 1km grid covering the whole US, here's all the squares with more than 20,000 people - 148 in New York, 4 in San Francisco

endless gridshift experiments get you different grid square totals but the Upper East Side in NYC is always the population density champion

in a few cases you get seemingly strange results, until you look more closely (e.g. think 'correctional facilities')

if you cheat, draw a single rotated, non-square shape around the highest density area you can find in New York City you can get a figure of about 75,000 people - the max in my European example was about 53,000, in the Barcelona Metropolitan Area (L'Hospitalet de Llobregat)

European levels of density can be found in a few places, including Madison, Wisconsin (I'll leave people to argue amongst themselves about the cheese)

hey, the metric system is a conspiracy, what about square miles? I wanted to compare my previous UK and European results to the US using the same metrics, but here's what I think is the highest density NYC square mile

lots of nerd notes in the blog, as well as link to folder with the maps, but no matter what 1km grid you use, San Francisco has higher maximum densities than London, and New York beats Paris and Barcelona easily (though with slightly higher buildings!)

US Census nerds/data nerds - the median census block in 2020 had 14 people in it, but this one at UCLA had a bit more than that

here's the San Francisco max density squares but this time with a map that allows you to see the streets - and note that if you shift the grid a bit you only get 3 squares but you do get one with more than 30,000 people in it

to end this thread for now, here's a comparison of the highest density square km in the US (Upper East Side, New York) and the highest density square in Europe (Barcelona Metropolitan Area, L'Hospitalet de Llobregat specifically)

for anyone wondering about how students get counted in the US Census, and where, this is what the US Census Bureau says about it

adding the 3 highest density 1km squares in Detroit to the thread, for @CONYERSTHREE

the highest density 1km square in Los Angeles is basically the same as the highest density in London, which surprised me a little

I did every single square km in the United States, although I was only really trying to find the maximum values - but I also have less dense areas, like these ones

one of the slightly less dense locations, this one just on the edge of Las Vegas (the houses are now complete so the population today will be higher than 7!)

occasionally you stumble across a lower density area, although I think this one is an overestimate

these were all the 1km squares in the lower 48 states that had at least one person in them - the median value is 24 people, the mean is 185 people, but the layer itself is quite a useful output from this little density mapping experiment

every so often you get a square like this, which you think MUST be an error and then you find out it's some kind of prison (in this case Arizona State Prison Complex, Tucson) - which is not really the kind of population density I was looking for