The Old Customs House, also called the Old Post Office, is a historic building located at the corner of Clinch Avenue and Market Street in Knoxville, Tennessee, United States. Completed in 1874, it was the city's first federal building. It housed the federal courts, excise offices and post office until 1933. From 1936 to 1976, it was used by the Tennessee Valley Authority for offices. Expanded in 2004, the building is home to the East Tennessee History Center, which includes the Lawson McGhee Library's Calvin M. McClung Historical Collection, the Knox County Archives, and the East Tennessee Historical Society's headquarters and museum. The building is listed on the National Register of Historic Places for its architectural significance.

The Tennessee Valley Authority (TVA) is a federally owned electric utility corporation in the United States. TVA's service area covers all of Tennessee, portions of Alabama, Mississippi, and Kentucky, and small areas of Georgia, North Carolina, and Virginia. While owned by the federal government, TVA receives no taxpayer funding and operates similarly to a private for-profit company. It is headquartered in Knoxville, Tennessee, and is the sixth-largest power supplier and largest public utility in the country.