U.S. Department of Commerce

How the 2008 TIGER/Line Shapefiles are Organized

The organizational structure of the TIGER/Line Shapefiles is based on the hierarchical relationship of geographic entities (see diagram in [PDF] format or a [TEXT] description).


Nation-Based Files

Entities that are defined independently from states and counties, such as American Indian Areas, are available in nation-based shapefiles that encompass the entire country. Though defined within states, county boundaries are available in nation-based as well as state-based shapefiles. The following layers are included:

To download these layers, click on the 2008 TIGER/Line Shapefiles download page.


American Indian Area-Based Files

The following layers are available by American Indian Area:

To download these layers, click on the 2008 TIGER/Line Shapefiles download page and select an American Indian Area.


State-Based Files

Entities such as school districts and congressional districts that are defined within states and can cross county boundaries are represented in state-based shapefiles. Though defined within counties, blocks, block groups, census tracts, and county subdivisions are available in state-based as well as county-based shapefiles. Though defined within states, counties are available in state-based as well as nation-based shapefiles. The following layers are included:

To download these layers, click on the 2008 TIGER/Line Shapefiles download page and select a state.


County-Based Files

Entities that are defined within counties and do not cross county or state lines such as census tracts and voting districts are represented in county-based shapefiles. Though defined within counties, blocks, block groups, census tracts, and county subdivisions are available in state-based as well as county-based shapefiles. The following layers are included:

To download these layers, click on the 2008 TIGER/Line Shapefiles download page. Select a state, and then select a county.



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