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:
- American Indian/Alaska Native/Native Hawaiian Area (Census 2000 and current)
- American Indian Tribal Subdivision (Census 2000 and current)
- County and Equivalent (Census 2000 and current)
- Combined New England City and Town Area (current)
- Combined Statistical Area (current)
- Metropolitan Division (current)
- Metropolitan/Micropolitan Statistical Area (current)
- New England City and Town Area (current)
- New England City and Town Area Division (current)
- State and Equivalent (Census 2000, current, and Economic Census)
- Urban Areas (Census 2000 and corrected Census 2000)
- 3-Digit ZIP Code Tabulation Area (Census 2000 and 2002)
- 5-Digit ZIP Code Tabulation Area (Census 2000 and 2002)
- Military Installation (current)
American Indian Area-Based Files
The following layers are available by American Indian Area:
- American Indian Tribal Subdivision (Census 2000 and current)
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:
- Alaska Native Regional Corporation (Census 2000 and current)
- Block (Census 2000 and current)
- Block Group (Census 2000)
- Census Tract (Census 2000)
- Commercial Region (Economic Census)
- 110th Congressional District (Congress elected in 2006)
- 108th Congressional District (Congress elected in 2002)
- Consolidated City (Census 2000, current, and Economic Census)
- County and Equivalent (Census 2000, current, and Economic Census)
- County Subdivision (Census 2000 and current)
- Place (Census 2000, current, and Economic Census)
- 1-Percent Public Use Microdata Area (Census 2000)
- 5- or 10-Percent Public Use Microdata Area (Census 2000)
- Elementary School District (Census 2000 and current)
- Secondary School District (Census 2000 and current)
- Unified School District (Census 2000 and current)
- State Legislative District—Lower Chamber (Census 2000 and current)
- State Legislative District—Upper Chamber (Census 2000 and current)
- Urban Growth Area (Census 2000 and current)
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:
- All Lines (current)
- Area Hydrography (current)
- Area Landmark (current)
- Point Landmark (current)
- Block (Census 2000 and current)
- Block Group (Census 2000)
- Census Tract (Census 2000)
- County Subdivision (Census 2000 and current)
- Subbarrio (Census 2000 and current)
- Traffic Analysis Zone (Census 2000)
- Voting District (Census 2000)
- Address Range-Feature Name Relationship File (current)
- Address Ranges Relationship File (current)
- Feature Names Relationship File (current)
- Other Identifiers Relationship File (current)
- Topological Faces (2-Cells With All Geocodes) Relationship File (current)
- Topological Faces-Area Landmark Relationship File (current)
- Topological Faces-Area Hydrography Relationship File (current)