In St. Louis County, Missouri State Route 370 is an expressway, running from the Missouri River to I-270. This section completes the by-pass aroudn St. Charles, and provides a alternate to the old and heavly used Blanchette Bridge on I-70 to the south. MO 370 passes through the following towns in St. Louis County. Bridgeton
Hazelwood Missouri State Route 370 does not multi-plex with any other route in St. Louis County. Missouri State Route 370 intersects the following highway in St. Louis County. Interstate 270, at Bridgeton.