U.S. Fish & Wildlife Service

Data Layer:  CONGRESSIONAL DISTRICT

You are invited to read the definitions of terms used in this data standard.

Name Congressional District
Description
 The data layer consists of digital information input by the Census Bureau depicting the boundaries of the Congressional Districts. This may vary by Congress, as there could be redistricting changes every two years. 
Source
 The Census Bureau maintains a site with the current and past Congressional District coverages (103rd, 104th, 105th, 106th and 107th) and metadata at http://www.census.gov/geo/www/cob/cd_metadata.html.  Coverages are available by state or for the entire country in ARCExport or Shapefile format.

ESRI has a data site at http://www.esri.com/data/download/census2000_tigerline/index.html where TIGER data, including Congressional District data, can be converted to shapefiles and downloaded, either by county or data layer. Only the 104th Congressional District information is available here.
Reference(s)

Part 270, FW 6, Data Management and Standards, dated September 30, 2002.

Documentation on Congressional District data and other Census Bureau TIGER data sets is available at http://www.census.gov/geo/www/tiger/.
Use Instructions
 As of the approval date, this data standard will be used whenever Congressional District spatial data are required for an application. This data standard also needs to be used in conjunction with the Congressional District Data Element Standard, which can be viewed at this site. 

To ensure compliance with the Service Information and Technology Architecture (SITA), Service staff are strongly encouraged to utilize this data layer in existing systems, data sets, databases, and information applications. Where existing systems and data-related items are not in compliance, they should be modified to achieve compatibility and implement this data standard.

The Census Bureau source site identified above provides data in Arc/Info E00 format, shapefile format, and Arc generate and ungenerate formats with all relevant attributes converted from the native TIGER format.  Data are provided for the 103rd, 104th, 105th and 106th Congress. Generally, you will want to use the most current data, but there may be cases where the historic district boundaries are needed for analytical purposes. For many areas in the country, there may not be yearly changes, in which case any of the data sets can be used.
Tools
The native data format for Congressional District data is TIGER. Since many geographic information systems (GIS) cannot use TIGER data directly, conversion programs are needed.  Some software programs incorporate an import function for TIGER data.  Arc/Info is a good example. For others, there are separate translators. The two listed below are just examples; both have been tested and work well.

A TIGER to shapefile (ArcView) or mif (MapInfo) format converter can be tested at http://www.census.gov/geo/www/tiger/.   This is an inexpensive converter that works well, but only works with TIGER data.

The ESRI source site referenced above converts the TIGER data to a shapefile before you download it, but only works on the 104th Congressional District data available at the ESRI site. 

The ARCExport and shapefile formats that the Census Bureau also supplies the data in can be utilized by many GIS software programs and are much easier to convert than the TIGER data.
Phase Adopted
Approval Date July 13, 1999
Validation Date January 3, 2005
Data Steward Deb Southworth Green, National FWS GIS Coordinator, Branch of Data and System Services, Division of Information Technology Management

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These pages are maintained by the U.S. Fish and Wildlife Service, Division of Information Technology Management. Please feel free to contact Deb Southworth Green with any questions and comments.

Keywords=congressional, districts, state, data, standards, layers
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