Obion County is a county located in the northwest corner of the U.S. state of Tennessee. As of the 2020 census, the population was 30,787. The county seat is Union City. The county was formed in 1823 and organized in 1824. It was named after the Obion River.

Reelfoot Lake is a shallow natural lake located in the northwest portion of the U.S. state of Tennessee, in Lake and Obion Counties. Much of it is swamp-like, with bayou-like ditches connecting more open bodies of water called basins, the largest of which is called Blue Basin. Reelfoot Lake is noted for its bald cypress trees and its nesting pairs of bald eagles.