Lake County is a county located in the northwest corner of the U.S. state of Tennessee. As of the 2020 census, the population was 7,005, making it the fifth-least populous county in Tennessee. Its county seat is Tiptonville. It shares a border with Kentucky to the north and is separated from Missouri to the west by the Mississippi River.

Tiptonville is a town in and the county seat of Lake County, Tennessee, United States. Its population was 2,439 as of the 2000 census and 4,464 in 2010, showing an increase of 2,025. It is also home to the Northwest Correctional Complex, a maximum security prison, known for once housing mass murderer Jessie Dotson.