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.

Union City is located in Obion County, Tennessee, United States. 11,170 people were living in the town as of the 2020 census. It is the principal urban settlement of the surrounding micropolitan area, which includes Obion County and Fulton County, Kentucky. Union City is home to Discovery Park of America which is a world-renowned encyclopedic museum with many exhibits pertaining to local history, as well as state, national, and world history, science, technology, and art.