Hempstead County is a county located in the U.S. state of Arkansas. As of the 2020 census, the population was 20,065, down from 22,609 at the 2010 census. The county seat is Hope. Hempstead County is Arkansas's fourth county, formed on December 15, 1818, alongside Clark and Pulaski counties. The county is named for Edward Hempstead, a delegate to the U.S. Congress from the Missouri Territory, which included present-day Arkansas at the time. It is an alcohol prohibition or dry county.