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Finding GIS data for the U.S.

New GIS users are pleased to discover a vast amount of free downloadable GIS data compiled by U.S. government agencies. The trick is knowing which data are available from which agencies. The Great Lakes Information Network provides Great Lakes Region data with detailed boundaries and added fields for things like basin statistics, population estimates, or contact information for political representatives.

The table below summarizes U.S. federal sources for GIS vector data often used by the Great Lakes Information Network to compile binational data and create GIS web tools and maps.

Data Source Types of data available Examples of use
United States Census Bureau
TIGER Products
Political borders such as municipality boundaries, Landmarks, Roads, CENSUS, and more The Great Lakes Commission joined congressional district boundaries with House of Representatives Congress member names and added contact information for each representative, Great Lakes basin information, and Great Lakes restoration projects (

CENSUS data is available that has already been combined with political boundaries such as counties and states. CENSUS data is also available in smaller divisions such as block groups which are useful to estimate populations when government boundaries do not apply, such as for user-defined buffer areas or in watersheds.
United States Department of Agriculture
Geospatial Data Gateway
US hydrology & hydrography (watersheds, lakes, rivers, etc.), Land Cover, Soils, Topography, and more Watershed boundaries can be overlaid with population and political boundaries to understand which areas are hydrologically connected for decisions on water conservation and healthy integrated water use.

Land Cover data is available for different time periods which can be used to estimate urban growth.
National Centers for Environmental Information
Great Lakes bathymetry Bathymetry for the Great Lakes is useful for research and creating simple fishing maps.

Tips to locate GIS data:

  • Get to know the terminology of what you are looking for, such as bathymetry for lake depth versus topography for the earth surface.
  • When looking for international data determine the terms commonly used by that country. For example, what is often referred to as drainage areas in Canada is commonly referred to as watersheds in the U.S.
  • Beyond federal agencies, local sources such as counties, states, or councils of governments might have additional data.
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