Historical Statistics of the United States: Earliest Time to the Present. (2006, 5 vols.)
6th floor HA202.A385 2006
Statistical Abstract of the United States (1878-2012)(United States Census Bureau)
Covers social, political, and economic orgainzation of the United States. Public access.
United States Census Bureau
Data about the American people and the economy. Public access.
Statistical information from over 100 U.S. federal agencies. Public access.
Bureau of Labor Statistics, United States Department of Labor
Includes U.S. prices, employment and productivity statistics. Public access.
NHGIS National Historical Geographic Information System
Free, aggregate U.S. census data and GIS-compatible boundary files for 1790-2012
U.S. Census and Demographic Information (This research guide by Catherine Morse at the University of Michigan Library includes a section on historical census data in addition to more general tips on using the U.S. Census)