Structural inequalities in these areas of America are particularly vulnerable to Covid-19. Take a look at these maps.
Studying the second map, it looks like the hardest hit areas are in the northeast generally, and then where there are large cities, such as LA, Chicago, Miami, Atlanta, etc.
It is claimed that the South is notably vulnerable, but so far that theory doesn’t seem to be holding up. Mississippi, Alabama, South Carolina and Arkansas seem to be less affected than the northern states. That could change of course, but the rate of infection seems to be tapering off at this point.