This tabulation from the 2008-2012 American Community Survey shows estimates of the citizen voting age population by race for small areas of geography.
The downloadable files show the population 18 and older by citizenship status and race for the nation, states, District of Columbia, Puerto Rico, counties, minor civil divisions, places, tracts and block groups. The files reflect both the population living in housing units and in group quarters, such as college dormitories. The new files and technical documentation along with previous versions of the files can be found on the Census Bureau’s Redistricting Data website.
This is the fourth year in a row that the American Community Survey has produced estimates of this population for even the smallest geographic areas. Prior to the American Community Survey, communities would have to wait 10 years for an update on the citizen voting-age population.