Congressional District Database for the 117th US Congress (April 2021 data)
Confused about which Congress is which?Members of the 117th US House of Representatives were elected on November 3, 2020, and sworn-in on January 3, 2021. Note that new congressional district boundaries were established in 43 of the 50 states following the 2010 US Census, as required by the US Constitution. Congressional District Database for the 117th Congress is based on the most recent district boundaries, including the states of Virginia, North Carolina, Florida, and Pennsylvania, which recently redrew their congressional district boundaries, as required by the courts.
The Congressional District Database lists the current congressional district of the new 117th Congress for each ZIP+4 defined by the US Postal Service. The ZIP+4 records of this database provide the necessary resolution to find the correct district within a ZIP code which lies in two or more districts. Do you know: more than 6000 5-digit ZIP codes lie in two or more districts! A single ZIP+4 record normally applies to a single block of a street or sometimes to a single address of a street, which means that this database resolves the district correctly down to the block or address level.
If you have 5-digit ZIP codes but not the ZIP+4s, you can find the correct district more than 90 percent of the time using only the 5-digit ZIP code. Click here for more information.
Please note that this database does NOT contain street address information. This database is useful for finding the district if you already have ZIP+4 data. If you have the street address (but NOT the ZIP+4) then you need to use an address matching product such as our Perfect Address product line to find the congressional district. Click here for more information.
Members of the 117th Congress
The database also includes a file containing a list of all the states and territories, with the 2-digit state FIPS code assigned to each state by the US Government.
We update every record in Congressional District Database monthly, so you always receive the latest and most up-to-date data. You can't get more accurate and timely ZIP code data from any other source! We license our ZIP code data directly from the US Postal Service, and collect and cross-check all the other data continuously from a variety of sources.
The concise-format version lists ranges of active ZIP+4s, with about 2.5 million range records in a single ASCII file covering the entire country.
You may download any of these formats after you place your order.
Record Layout of the Full-format Files
All fields are treated as text fields, but the fields are NOT quote delimited, to conserve file space. Fields do not contain embedded commas. For numeric fields, leading zeroes are retained in all cases. This prevents problems importing the data into database programs.
In each record, the fields contain data relating to the particular ZIP+4 identified by the ZIP+4 field.
The City name is the city in which the ZIP+4 lies, as defined by the USPS.
The city Place FIPS code comes from the Census Bureau Place FIPS file, which does not always agree with US Postal Service naming and spelling for a given place name. Where no matching city Place FIPS code can be determined, the city FIPS code is set to 00000.
The County FIPS code is a 3-digit numeric field containing a unique numeric code assigned to each county within a state by the US government.
The Congressional District field contains the numeric district number (with leading '0' if less than 10) within the state for that particular ZIP+4. A single ZIP+4 record normally applies to a single block of a street or sometimes to a single address of a street, which means that this database resolves the district correctly down to the block or address level. If a 5-digit ZIP code lies in multiple districts (more than 6000 5-digit ZIP codes lie in multiple districts) the ZIP+4 records provide the necessary resolution to find the correct district within the ZIP code. For states with only a single congressional district, the congressional district field contains 00.
Each record ends in an ASCII CR-LF pair.
Record Layout of the Concise-format File
Each record of the concise-format file contains exactly five CSV text fields, defined as follows:
Each record ends in an ASCII CR-LF pair.
The Plus 4 Low and Plus 4 High range define a group of 1 to 9,999 active "+4s" that all belong to a single 5-digit ZIP code, all lie in a single congressional district, and all belong to a single state. All possible "+4s" that fall within the range are valid "+4s", as defined by the USPS.
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