Polk County is a county located in the U.S. state of Arkansas. As of the 2020 census, the population was 19,221. The county seat is Mena. Polk County is Arkansas's 48th county, formed on November 30, 1844; it was named for James K. Polk, 11th President of the United States.

Mena is a city in Polk County, Arkansas, United States. It is also the county seat of Polk County. The population was 5,558 as of the 2020 census. Mena is included in the Ark-La-Tex socio-economic region. Surrounded by the Ouachita National Forest, Mena is a gateway to some of the most visited tourist attractions in Arkansas.