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. The following layers are included:

• American Indian/Alaska Native/Native Hawaiian Area (Census 2000 and current)
• American Indian Tribal Subdivision (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 and current)
• 3-Digit ZIP Code Tabulation Area (Census 2000)
• 5-Digit ZIP Code Tabulation Area (Census 2000)

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. The following layers are included:

• Alaska Native Regional Corporation (Census 2000 and current)
• 110th Congressional District
• 108th Congressional District
• 106th Congressional District
• Consolidated City (Census 2000 and current)
• County and Equivalent (Census 2000 and current)
• Place (Census 2000 and current)
• 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)

County-Based Files

Entities that are defined within counties and do not cross county or state lines such as census tracts, block groups, and blocks are represented in county-based shapefiles (i.e. one shapefile for each county). 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)
• Topological Faces (2-Cells With All Geocodes) Relationship File (current)
• Topological Faces-Area Landmark Relationship File (current)
• Topological Faces-Area Hydrography Relationship File (current)

American Indian Area-Based Files

The following layers are available by American Indian Area:

• American Indian Tribal Subdivision (Census 2000 and current)