High Quality Content by WIKIPEDIA articles! Route 30 is a highway in eastern Missouri. Its eastern terminus is at the Interstate 55/Interstate 44 junction in St. Louis. Its western terminus is at Interstate 44 in St. Clair. In St. Louis, the section between Interstate 44 and Route 366 is part of historic U.S. Route 66 and is marked as such. In the St. Louis area, it is known as Gravois Avenue or Gravois Road. Further south, Gravois Rd is used to mark the old section of the highway where the newer, divided highway rerouted Highway 30.