New Madrid County (pronounced /njuː ˈmædrɨd/) new-MAD-rid) is a county located in the Bootheel of the U.S. state of Missouri. As of the 2010 census, the population was 18,956. The largest city and county seat is New Madrid, located on the northern side of the Kentucky Bend in the Mississippi River, where it has formed an oxbow around an exclave of Fulton County, Kentucky.