one good place to go is IPUMS. IPUMS is run by the Minnesota Population Center at the University of Minnesota. The website contains microdata from a large number of surveys including the Census, American Community Survey, and Current Population Study. From the IPUMS website:
The Integrated Public Use Microdata Series (IPUMS-USA) consists of more than fifty high-precision samples of the American population drawn from fifteen federal censuses and from the American Community Surveys of 2000-2011. Some of these samples have existed for years, and others were created specifically for this database. These samples, which draw on every surviving census from 1850-2000, and the 2000-2011 ACS samples, collectively constitute our richest source of quantitative information on long-term changes in the American population. However, because different investigators created these samples at different times, they employed a wide variety of record layouts, coding schemes, and documentation. This has complicated efforts to use them to study change over time. The IPUMS assigns uniform codes across all the samples and brings relevant documentation into a coherent form to facilitate analysis of social and economic change.
IPUMS is not a collection of compiled statistics; it is composed of microdata. Each record is a person, with all characteristics numerically coded. In most samples persons are organized into households, making it possible to study the characteristics of people in the context of their families or other co-residents. Because the data are individuals and not tables, researchers must use a statistical package to analyze the millions of records in the database. A data extraction system enables users to select only the samples and variables they require.
IPUMS-International is the world’s largest collection of publicly available individual-level census data. IPUMS-International integrates samples from population censuses from around the world taken since 1960. Scholars interested only in the United States are better served using IPUMS-USA, which is optimized for U.S. research.
IPUMS-CPS is an integrated set of data from the March Current Population Survey (CPS), beginning in 1962 and continuing until the present. This harmonized dataset is also compatible with the data from the U.S. decennial censuses that are part of the IPUMS-USA. Researchers can take advantage of the relatively large sample size of IPUMS-USA at ten-year intervals and fill in information for the intervening years using IPUMS-CPS.
So IPUMS is just a collection of data sets…big deal. Where is the value-added? Again from the IPUMS website:
IPUMS data is integrated over time and across samples by assigning uniform codes to variables. This process itself adds value to the data by fully documenting all codes and compiling all variable documentation in a hyperlinked web format. But we do many other things as well:
IPUMS creates a consistent set of constructed variables on family interrelationships for all samples. The “pointer” variables indicate the location within the household of every person’s mother, father, and spouse.
IPUMS data also includes harmonized income and occupation variables. The Census Bureau has reorganized its occupational and industrial classification systems in almost every census administered since 1850. Although IPUMS retains the original occupation and industry codes, a variety of occupation and industry variables have been created for long-term analysis. More information on these variables can be found on the Occupation and Industry Variables page.