Voter Registration and Turnout

Voting and Registration in the Election of ... Census Bureau. Current Population Survey

- estimates for nation and states by race, sex, Hispanic Origin (and age in some tables)
- election years only, 1970- (with some data back to 1960)
- pdf format

American National Election Studies, 1948-

- post election survey provides alternative source for estimating turnout, nation only
- interactive survey data analysis available through the SDA Archive at UC Berkeley

Individual secretary of state offices

The Secretary of State's office in most states provides recent registration stats online, in some cases down to the county and even precinct level.