Missouri Secondary State Route F is a north-south highway in Madison County. It runs in the Mark Twain Forest. This highway is on the westside of the Castor River. MO Sec St Rt F does not pass through any towns in Madison County. MO Sec St Rt F is not multi-plexed in Madison County. MO Sec St Rt F intersects the following highways in Madison County. Missouri State Route 72, near Junction City.