Government Information : General Resources

This might be the best place to start. Provides free online access to publications from the legislative, executive, and judicial branches of government.

USA.gov is the U.S. Government's official web portal. It is an easy-to-search, free-access website designed to give you a centralized place to find information from local, state, and US Government Agency websites.

Access to thousands of US Government web sites.

The Catalog of U.S. Government Publications (CGP) is the finding tool for federal publications that includes descriptive records for historical and current publications and provides direct links to those that are available online. Users can search by authoring agency, title, subject, and general key word, or click on "Advanced Search" for more.

You can look for census data here and also build maps.