OpenCongress API: OpenCongress brings together official government data with news and blog coverage to give users the real story behind each bill. The OpenCongress API also developers to access all this data for their website or application.
The TownMe API includes both read and write geo-related services. The read side has a reverse geocoder which helps translate coordinates into human readable elements or associations. For instance, give the API “37.78093,-122.409415″ and it will return information about the census tract, neighborhood, city, MSA, and state that contains these coordinates