Claiborne was born in Virginia in 1775. He studied law and moved to Tennessee to practice. He was elected to Congress from Tennessee and supported President Thomas Jefferson on several issues. In 1801, President Jefferson appointed him to be the second governor of the new Mississippi Territory, following Governor Winthrop Sargent. He soon moved the territorial capital from Natchez to Washington, a few miles away. Governor Claiborne helped to open the port of New Orleans for American trade on the Mississippi River and settle controversial land title disputes. He also secured the right to use the Natchez Trace as a mail route and is noted for setting a reward that led to the capture of the notorious Mason-Harpe gang of robbers on the roadway. When the Louisiana Purchase occurred in 1803, Claiborne was named governor of the new Louisiana Territory and moved to New Orleans. Claiborne County, Mississippi, is named for him.