Black business has always come in blocks.

How these were found, and why the test is strict. These are not chosen. A street appears here when the directory holds 3 or more Black-owned businesses on it at different house numbers — several businesses at one address is a building, or a mistake, not a block. That test matters because earlier passes on this data found clusters that were fabricated: forty businesses filed at a single real address in Atlanta, and Chicago listings given a neighboring street. Every group above was checked against it, and a block only means what the addresses say — that these businesses stand near one another, not that anyone has vouched for the street.