Westfield, Ala. (Mays), 660 homers/1,403 population, 0.47 HR/person
Donora, Pa. (Griffey/Musial), 1,105 homers/5,253 population, 0.21 HR/person
Now, in no way is this a scientific study. It's something I threw together on a Sunday afternoon watching football, using 2000 census data. Numbers for Sudlersville, Md., were not available before 1990, so it's likely that fewer than 396 people lived in the hamlet when Foxx was born in 1907. But these are the numbers available, so that's what I used. And to keep it consistent, I went with the 2000 census data for all towns. Ideally, I would've averaged the populations for the towns and cities over the time period from the first-born player on the list to the most recent, but that would involve numbers and formulas that no one should be playing around with on a Sunday afternoon.