I guess - mind, this is an uneducated guess - that population density is more of a marker here than sheer population. (Or area!)

After all, high population density leads to more interactions with other people, a small portion of which escalate to violence.

Also, if I was aiming for a career in violent crime, I'd pick a place with lots of potential victims. After all, mugging the other inhabitant of East Nowhere, Alaska pretty much means you've cornered that market and need to move elsewhere.

(The underlying assumption is that the percentage of people murdered by their partner or close friends is pretty much even across the country, and that what varies is the - hm - opportunistic murder rate.)

> mugging the other inhabitant of East Nowhere, Alaska

You might also find yourself having an "accident" that makes you bear food pretty quick.

To your point, being a career criminal in a dense urban area also probably increases the likelihood you won't be caught after committing a crime and be able to go on to commit others.

Population density being correlated with crime rate is more mysterious than it would seem at first. After all, people live in cities because many things benefit from economies of scale. Why doesn't policing?

First of all, it seems to make sense that crime also benefits from the same economies of scale. This could offset the improvement in policing.

Secondly, policing becomes harder in a city due to increased anonymity and the ease of hiding in plain sight. As a city grows, more and more people don't know each other. This reduces the effectiveness of social policing.

Is policing the thing that stops crime? There are obviously many parts to it including policing but a lot of things have gone wrong before the police were needed.

It's much less mysterious when you consider socioeconomic factors. In particular, they concentrate in neighborhoods which are vestiges of midcentury economies of scale (i.e. factory jobs), and are now hopeless. Urban police are pretty good at stopping violent crime from leaking into white professional neighborhoods, which is arguably city institutions' true priority.

Police tactics are only going to get you so far in communities that (justifiably) see the police as an oppressive enemy faction, where witnesses don't talk to detectives and juries don't convict.

Also, residents of East Nowhere tend to carry guns and shorten the careers of professional muggers dramatically.