The cartographic boundary files are simplified representations of selected geographic areas from the Census Bureau’s Master Address File/Topologically Integrated Geographic Encoding and Referencing (MAF/TIGER) System. These boundary files are specifically designed for small scale thematic mapping.

When possible, generalization is performed with intent to maintain the hierarchical relationships among geographies and to maintain the alignment of geographies within a file set for a given year.

To improve the appearance of shapes, areas are represented with fewer vertices than detailed TIGER/Line equivalents. Some small holes or discontiguous parts of areas are not included in generalized files.

Generalized boundary files are clipped to a simplified version of the U.S. outline. As a result, some offshore areas may be excluded from the generalized files.

• Simplified shapes improve the appearance of geographic areas when displayed at small scales.
• These boundary files take up less disk space than their ungeneralized equivalents.
• Cartographic boundary files take less time to render on screen.

• These files should not be used for:
  • geographic analysis including area or perimeter calculation.
  • geocoding addresses.
  • determining precise geographic area relationships.
• Some small geographic areas are excluded from these files.
• Geographic areas may not align with the same areas from another year.

Visit the Cartographic Boundary File webpage to download these files.

The cartographic boundary files are named cb_yyyy_ss_<entity>_rr.zip where:

• yyyy = 4 digit year
  
• ss = state FIPS code or 'us' for a national level file
• entity = the entity name
• rr = resolution level
  • 500k = 1:500,000
  • 5m = 1:5,000,000
  • 20m = 1:20,000,000

For a list of entity names and their descriptions for the cartographic boundary files, please see the Entity Name Description files below:

The 2010 cartographic boundary files are named gz_2010_ss_lll_vv_rr.zip where:

• ss = state FIPS code or 'us' for a national level file
• lll = summary level code
• vv = 2-digit version code
• rr = resolution level
  • 500k = 1:500,000
  • 5m = 1:5,000,000
  • 20m = 1:20,000,000

For a complete list of summary level codes for the cartographic boundary files, please see our Summary Level Codes Page.

abss_vvv_shp.zip

where:

• ab = geographic area abbreviation
• ss = state FIPS code
• vvv = 2 or 3 character file vintage

After files have been downloaded and unzipped, the .zip extension and the file format abbreviation are dropped, and the proper file format extension is appended. An unzipped shapefile is composed of a .shp file, a .shx file, and a .dbf file.

The table below provides a complete list of the file name components and gives examples of complete file names. You can access the FTP directories to download the shapefiles by clicking on the Geographic Area name.

¹  State FIPS Codes = 01-78, National File=99
²  d Indicates a Decennial Census Activity