Dollar General, Dollar Tree, and Family Dollar have spread across low income America while full service groceries thinned out. The data shows it plainly: the poorest quartile of US counties carries about 20.6 dollar stores per 100,000 residents, against 12.8 in the least poor quartile, roughly 60 percent denser.
Here every county is a single light. Its place along the floor is set by poverty, lowest on the left, highest on the right. Its height is dollar store density. Toward the poor edge the lights climb and crowd together into a rising bloom, with a trend line marking the average. Move your pointer, or tap, onto a light to read its county.