The city was named for state legislator William Claiborne Dunlap, who played a prominent role in the county's creation.

Coke, which is created by heating coal and removing its volatile matter, is used primarily as a deoxidizing agent in the production of pig iron.

To convert coal mined on nearby Fredonia Mountain into coke, Douglas built the first of 268 ovens.

Although Douglas went bankrupt in 1904, the Chattanooga Iron and Coal Company purchased the ovens, and continued producing coke until 1927.

U.S. Route 127 (called "Rankin Avenue" in Dunlap), which traverses much of the Tennessee section of Sequatchie Valley, connects Dunlap to Pikeville and Crossville to the north and Chattanooga opposite Signal Mountain to the southeast.

111, which intersects US 127 a few miles north of Dunlap, connects the city to Chattanooga to the southeast and Spencer atop the plateau to the west.

According to the United States Census Bureau, the city has a total area of 8.6 square miles (22 km2), all land.

As of the 2020 United States census, there were 5,357 people, 2,007 households, and 1,414 families residing in the city.

[15] The Mount Airy Golf Course is located just north of the city at the Sequatchie-Bledsoe county line.