Missouri Secondary State Route O is a north-south highway in Southeastern Warren County. It runs from Missouri State Route 47, near Marthasville to Missouri Secondary State Route M/T, near Foristell. MO Sec St Rt O does not pass through any towns in Warren County. MO Sec St Rt O is not multi-plexed in Warren County. MO Sec St Rt O intersects the following highways in Warren County. Missouri State Route 47, near Marthasville.
Missouri Secondary State Route M, near Foristell. Missouri Secondary State Route T, near Foristell.
