Sequatchie County, the youngest and smallest of the three counties comprising Sequatchie Valley, has an area of two hundred fifty square miles. It was formed by an act of the General Assembly of the State of Tennessee, December 9, 1857, from territory belonging to Hamilton County, or rather that which formerly was a part of Bledsoe and Marion Counties.

The county was named for the valley in which it is located. The valley was named for the Cherokee Chief, Sequachee, who signed a treaty with the colonial government of South Carolina. Historians who have studied the language and lore of the Cherokee differ over the exact meaning of the word, but the general consensus is “opossum, he grins or runs.”

Sequatchie County is located in the center of the valley. It is bordered on the north by Bledsoe County, east by Hamilton County, south by Marion County, and on the west by Grundy County and Van Buren County.
 

The first county court met at the home of Joel Wheeler in the Fillmore Community on the first Monday in January of 1858. It was decided to locate the county seat at a more centrally located spot and a site was selected on property owned by William Rankin at Coops Creek.
 

On June 12, 1858, the name was officially changed to Dunlap in honor of William Dunlap of Knox County who had supported the creation of Sequatchie County in the state legislature. Dunlap was incorporated as the Town of Dunlap and in 1941 was incorporated as the City of Dunlap, and remains as the only incorporated area inside the county.

Dunlap has a mayor-commissioner form of government.