Census Atlas of the United States

The U.S. Census Bureau has published its first comprehensive atlas of population and housing since 1920. While you can purchase the atlas for $165, the Bureau has made the entire atlas available online in PDF format for free. While the individual chapter files are large and the data is based on the 2000 Census, he maps are stunning and gorgeous. The atlas even includes maps of metropolitan areas and cities with demographic data based on individual census tracts!