"IPUMS provides census and survey data from around the world... IPUMS integration and documentation makes it easy to study change, conduct comparative research, merge information across data types, and analyze individuals within family and community context. Data and services are available free of charge.
"In collaboration with 105 national statistical agencies, nine national archives, and three genealogical organizations, IPUMS has created the world’s largest accessible database of census microdata. IPUMS includes almost a billion records from U.S. censuses from 1790 to the present and over a billion records from the international censuses of over 100 countries. We have also harmonized survey data with over 30,000 integrated variables and 150 million records, including the Current Population Survey, the American Community Survey, the National Health Interview Survey, the Demographic and Health Surveys, and an expanding collection of labor force, health, and education surveys. In total, IPUMS currently disseminates integrated microdata describing 1.4 billion individuals drawn from over 750 censuses and surveys.
"In addition to census and survey microdata, IPUMS integrates and disseminates the nation’s most comprehensive database of area-level census data and electronic boundaries describing census geography from 1790 to the present. IPUMS NHGIS includes 366 billion data points and 28 million map polygons describing U.S. Census geographic units. IPUMS Terra archives and disseminates a third class of data: raster data derived from satellite imagery, climate models, and other sources."