Political Science

US Government Data

• Data.gov 
• Census data
• American Community Survey
• American Housing Survey
• Bureau of Transportation

Maps/GIS

• Sanborn Map collection (Library of Congress)
• Suffolk County GIS
• Bureau of Land Management gallery (public lands)
• SBU Libraries Map Collection

Institutions at the local and regional level are a good source of data. Search for the planning department of a municipality to find a variety of information including data sets, maps, codes, and other resources. 

This is a short, representative list of examples:

• New York
  • NYC Open Data
  • NYC Planning
  • NYS GIS Clearinghouse
  • Nassau County Planning Department
  • Suffolk County Open Data
• Chicago Metropolitan Agency for Planning
• New Orleans Regional Planning Commission
• San Francisco Planning