U.S. Federal Route 69 runs briefly in Southeastern Platte County. This is the first county in Missouri it runs through since it enters from Kansas. U.S. Rt. 69 passes through the following towns in Platte County. Riverside Northmoor U.S. Rt. 69 is multi-plexed in Platte County. Interstate 635, at Riverside. Missouri State Route 9, at Riverside. U.S. Rt. 69 intersects the following highways in Platte County. Interstate 635, at Riverside.