JF Ptak Science Books Quick Post
[With thanks to Andrea Pitzer for surfacing this map today, and also to Slate Vault's Rebecca Onion for the story on the map, here.] All that I've done below is post some of the detail of the Library of Congress copy of this map so that county details are clearly visible.
Lynchings by states and counties in the United States, 1900-1931 : (data from Research Department, Tuskegee Institute) ; cleartype county outline map of the United States, and printed by the American Map Company (NYC), ca. 1931. Source: the Library of Congress; follow for a downloadable 5 meg copy.