The House of Representatives website offers a service to find a specific representative by entering a ZIP code. The Senate website lists senators after users select a state in the drop-down menu at the top right of the page.
There are multiple resources on the web for finding a representative in the U.S. Congress. Most of these methods involve entering an address or a ZIP code, but more general lists can also be found. The House of Representatives website will display a map of the district lines after entering a ZIP. The Senate website will list your state's representatives after choosing the state from the menu in the top right. Both of these sites have lists of all representatives with their states, districts, and parties available if privacy concerns are an issue.
Representative listings can be found on other non-government sites such as CongressMerge and OpenCongress, which offer general listings and lookups by address and ZIP code. Congressional representative contact information can be found on all of these sites as well, along with THOMAS, the Library of Congress database, which has information for both the assemblies and the representatives themselves. Most Congressional representatives can be contacted through phone and email.