Topologically Integrated Geographic Encoding and Referencing

"TIGER" redirects here. For the American federal grant program, see Transportation Investment Generating Economic Recovery. For other uses, see Tiger (disambiguation).

Topologically Integrated Geographic Encoding and Referencing, or TIGER, or TIGER/Line is a format used by the United States Census Bureau to describe physical and cultural features such as roads, highways, city limits, rivers, and lakes, as well as areas such as census tracts. TIGER was developed to support and improve the Bureau's process of taking the Decennial Census.— Developed in collaboration with the United States Geological Survey during the 1980's, TIGER was the first nationwide digital map of roads, boundaries and water and was initially created for the 1990 Census to modernize the once-a-decade head count. However, its impact has extended well beyond its initial purpose by offering common map data in electronic form that powers today’s geographic information system industry. TIGER still serves as the basemap for many commercial and open-source map projects in very rural areas of the United States. However, commercial mapping companies now offer newer and more detailed mapping data in urban and high growth areas.

TIGER logo

The TIGER files do not contain the census demographic data, but merely the geospatial/map data. GIS can be used to merge census demographics or other data sources with the TIGER files to create maps and conduct analysis. TIGER data is available without cost because U.S. Government publications are required to be released into the public domain.

Coverage

The TIGER/Line shapefile data includes complete coverage of the contiguous United States, Alaska, Hawaii, Puerto Rico, the U.S. Virgin Islands, American Samoa, Guam, the Commonwealth of the Northern Mariana Islands, and the Midway Islands.

TIGER contains both land features such as roads, rivers, and lakes, as well as political and statistical areas such as counties, census tracts, and census blocks. Some of the political areas represented in TIGER are state and federally recognized tribal lands, cities, counties, congressional districts, and school districts. Others are statistical areas, including Metropolitan Statistical Areas (MSA), census tracts, census block groups, and census blocks. ZIP Code Tabulation Areas (ZCTA) are quasi-statistical areas which attempt to approximate, but do not exactly match, the delivery areas of USPS ZIP codes.^[1] ZIP codes are based on postal delivery routes and may not correspond to municipalities.^[2]

Future

TIGER data published through February 2007 (2006 Second Edition) were in a custom ASCII format formally known as TIGER/Line files. In 2008, data in shapefile format was published. Shapefiles are not topological, therefore they may contain sliver polygons when comparing TIGER/Line boundaries with other TIGER features. This mismatch was not inherent when the census TIGER/Line files were released in the original ASCII format. The Census Bureau has been offering TIGER/Line data as Geodatabases since 2017, and open-source Geopackages since 2024. These formats can maintain topological relationships between themes or 'layers'.

Additionally, the Census Bureau has made TIGER data available through WMS servers known as TIGERweb.^[3]