Tennessee's 1st congressional district is the congressional district of northeast Tennessee, including all of Carter, Cocke, Greene, Hamblen, Hancock, Hawkins, Johnson, Sullivan, Unicoi, Washington, and Sevier counties and parts of Jefferson County. It is largely coextensive with the Tennessee portion of the Tri-Cities region of northeast Tennessee and southwest Virginia. With a Cook Partisan Voting Index rating of R+30, it is the most Republican district in Tennessee.

Carter County is a county located in the U.S. state of Tennessee. As of the 2020 census, the population was 56,356. Its county seat is Elizabethton. The county is named in honor of Landon Carter (1760–1800), an early settler active in the "Lost State of Franklin" 1784-1788 secession from the State of North Carolina. Carter County is part of the Johnson City, TN Metropolitan Statistical Area, which is a component of the Johnson City–Kingsport–Bristol, TN-VA Combined Statistical Area, located in northeastern Tennessee.