You can scroll through this page to find lists of links organized by topic, or you can click directly on the topic in this table of contents and it will bring you directly to the correct list.
Census Data - US Census data at data.census.gov
Social Explorer - library database
An online data reference tool for the United States. It unlocks 220 years of U.S. Census data and makes them available in an easy-to-use fashion with data visualization, reporting and downloads.
Downloadable data files, documentations, and data-based research related to a wide range of social science areas. Guide to Searching ICPSR
Don't forget about your local public library or historical society. They will have local history information and archives, often online. For example: Westfield (MA) Athenaeum has an easy to find section on their site strictly for local history resources. In addition to what's offered online, you can always call or visit the librarians, and they will be more than happy to help!