Pendleton is an incorporated village in Warren County, Missouri, United States. It had an estimated population of 53 in 2007. Warren County is a county located in the U.S. state of Missouri. Warren County is part of the St. Louis Metro Area and is located west of the city on the north side of the Missouri River. As of 2008, the population was estimated to be 31,214. Its county seat is Warrenton. The county was organized on January 5, 1833, and is named for General Joseph Warren, who died in the Battle of Bunker Hill during the American Revolutionary War.