With Geocodio, you can upload a list of addresses, coordinates, or ZIP codes and receive the Congressional district information. Simply select "Congressional Districts" in Step 3 of the upload process.
You can download an example of the results when you add Congressional districts to a list of addresses here. You can download example of the results when you add Congressional districts to a list of latitude/longitude coordinates here.
Due to the irregular shape of Congressional districts, we strongly recommend using street addresses or coordinates if you have them.
If you only have ZIP codes, we will return likely districts. For spreadsheet uploads, we will return the most likely district (i.e. the Congressional district with the greatest amount of overlap with that ZIP code). In the API, we will return all of the possible Congressional districts, ranked by overlap. See more here.
You can also get Congressional districts back to the 113th Congress via both our API (go to API docs) and spreadsheet upload. (We do not support historical legislator information.)
You can opt to receive just the districts or also the contact and biographical information for each Senator and Representative. The Senator and Representative information is included in the lookup cost for Congressional districts. Select "Add legislator data" under "Congressional districts" in Step 3 of the upload process.
Requests are billed as geocode + Congress info (i.e., two lookups). For example, if you have 100 addresses that you want Congressional contact information for, that would count as 200 lookups.
You can calculate how much this will cost you and how long it will take here.
This data comes to us from the UnitedStates project on Github, an open source project maintained by journalists.