Desha County /dəˈʃeɪ/ is a county located in the southeast part of the U.S. state of Arkansas. As of the 2010 census, the population was 13,008, making it the fifty-sixth most populous of Arkansas's seventy-five counties. The county seat is Arkansas City. Located within the Arkansas Delta, Desha County's rivers and fertile soils led to prosperity under the cotton-driven economy of plantation agriculture. Following mechanization on the farm, Desha County saw a demographic and economic transformation.