Mercer County is a county located in the U.S. state of North Dakota. As of the 2010 census, the population was 8,424. Its county seat is Stanton. The county was created by the 1874-1875 territorial legislature and was named for William Henry Harrison Mercer (1844–1901), an early rancher who settled north of Bismarck in 1869. The county government was first organized on August 4, 1884.