Warren County is a county located in the eastern portion of the U.S. state of Missouri. As of the 2010 census, the population was 32,513. The county is located on the north side of the Missouri River. Its county seat is Warrenton. The county was organized on January 5, 1833, and named for General Joseph Warren, who died in the Battle of Bunker Hill during the American Revolutionary War.
Warren County is part of the St. Louis, MO-IL Metropolitan Statistical Area. The county is traversed by Route 94, called the "Missouri Weinstrasse" because of the many vineyards from Marthasville east into St. Charles County. Warren County is also part of the Missouri Rhineland, with award-winning wineries located on both sides of the Missouri River.