Route 340 is a highway in the St. Louis metropolitan area. Its western terminus is Route 100 (Manchester Road) in Ellisville, and its eastern terminus isat an intersection with Ferguson Avenue and Olive Boulevard in University City. The stretch of Route 340 between Manchester Road and the Interstate 64 / U.S. 40 / U.S. 61 interchange is known locally as Clarkson Road. The remainder of Route 340 between this intersection and its eastern terminus is variously known as Olive Boulevard (which does not connect with Olive Street in the city of St. Louis. Route 340 ends at Ferguson Avenue in University City, but Olive Boulevard continues to Skinker Boulevard on St. Louis city line.