An easy way to find your state representative's contact information is to go to your state legislature's website and use its directory to look up the representative for your district. You can also call your county registrar or other election agency and ask for assistance with contacting your representative.
If you are unable to find your state legislature's website, the federal government also provides a tool on USA.gov. This allows you to choose your state and find state and local government contact information for your area. Some non-profit organizations, such as Common Cause, also provide search tools that allow you to find your state representative. Many state representatives also maintain their own websites with contact information.
If you are trying to contact your representative in the U.S. House of Representatives, you can visit the House website at House.gov and search for the person who represents you. Once you have located the right person, click on the listed name. That takes you to your representative's website, which has all the necessary contact information including an easy-to-use email form. You can also look up your representative by name or state in the online directory provided on the website. If you prefer to contact him by phone, you can call the United States Capitol switchboard directly and ask to be connected to the right office.