Measuring America : the decennial censuses from 1790 to 2000
Reproduces decennial census schedules and forms, 1790 through 2000. Provides history of decennial census and specific questions.

Historical Census Browser
Population and housing data for all U.S. states and counties, 1790 to 1960, based on decennial census of population and housing. Provides basic counts of population and housing, including race, gender, and some measure of household size and composition. For 1840 to 1960, economic characteristics such as education and occupation are included. Later decades have many variables, including ancestry, literacy, and income variables.

Decennials - Census of Population and Housing
PDF-format versions of historic US decennial census volumes, 1790 to present. Topics covered include basic counts of population and housing, with race and gender, for the nation, states, counties, townships and municipalities, and some small areas (e.g., wards). From 1840 to present, social and economic information is provided.
Holdings: 1790 to present (backfile in progress: 1790-1860, 1990-2000 available)

IPUMS
REQUIRES FREE REGISTRATION. Census microdata from historic national censuses, U.S. and worldwide. Only provides microdata data sets, with data subsetting and extraction, and documentation. Frequency distributions and crosstabulations not provided.

ICPSR
USE OF ICPSR DATA REQUIRES STATISTICAL PROCESSING SOFTWARE AND GZIP DECOMPRESSION SOFTWARE. Direct-download access to social science quantitative data sets archived by ICPSR. Subjects covered include political science, sociology, demography, history, economics, communication, international relations, gerontology, public health, criminal justice, and education. The ICPSR archive includes almost all major studies in the social sciences, including the General Social Survey and International Social Survey Program, decennial Census of Population and Housing, American National Election Study, Eurobarometer, Voter News Service exit polls, US Congressional and UN roll call votes, National Crime Victimization Survey, and public opinion polls. Special topic archives, with limited interactive tabulation and extraction capability, cover health and medical care, international education, aging, criminal justice, and substance abuse and mental health.
Holdings: 1962-present.

iPOLL
REQUIRES FREE REGISTRATION. Question-level data from public opinion polls. Almost 400,000 questions from polls, 1935 to present, based upon Roper Center-archived surveys with US national adult samples or samples of large subnational populations. Links to Roper Center data catalog holdings are provided. RPOLL provides a less functional interface to iPOLL through LexisNexis Academic.
Holdings: 1935 to present. Updated daily.

Historical Statistics of the United States Millenial Edition
The best starting-place for statistical information on the United States, for the colonial era and 1790-2000 (including the Confederate States of America). Presents 37,339 data series on population (including vital statistics, immigration and emigration), work and welfare (including labor, slavery, education, health, economic inequality and poverty, social insurance and public assistance), economic structure and performance (includuing national income and national product, business cycles, prices, consumer expenditures, savings, capital, and wealth, business organization, and financial markets and institutions), business sectors and industries, and governance and international relations (including government finance, elections and politics, crime and law enformcement, wars, armed forces, and veterans, and international trade and exchange rates).