The Instructional Computing Group of Harvard University, in cooperation with Inter-university Consortium for Political and Social Research at the University of Michigan, has made a subset of historical data from U.S. decennial censuses from 1790 to 1860 available for forms-based querying on the web. Data availability varies by year and state. From 1790 to 1830, most data concerns population breakouts by age, sex, and free or slave. From 1840 to 1860 much more data is available, including occupation, education, churches, mortality, and property and wealth, among others. After year selection, users query the database for state(s) and variable(s). Data returned can then be sorted by variable. Data are available at the state and county level, although county querying is not possible. There is no facility at this time for downloading data to statistical programs; however, this is a small price to pay for a virtual treasure house of U.S. historical information.