The U.S. Census Bureau recently released its 2010 Guide to State and Local Census Geography. Here is some of the information included in the publication:

Basic information about the state or equivalent (population, land area, density, capitol, borders, etc)
History
American Indian Areas
Metropolitan and Micropolitan Statistical Areas and Related Statistical Areas
Counties
Congressional Districts
School Districts
State Legislative Districts
ZIP Code Tabulation Areas
Most Populous, Largest in Area, and Most Densely Populated Areas