Missouri Secondary State Route B runs north-south in Central Jefferson County. It runs from Missouri State Route 21/Business Missouri State Route 21, at Hillsboro, to Missouri State Route 30/Missouri Secondary State Rotue NN, south of Cedar Hill. MO Sec St Rt B passes through the following towns in Jefferson County. Hillsboro
Morse Mill MO Sec St Rt B is multi-plexed in Jefferson County. Missouri State Route 21, at Hillsboro. MO Sec St Rt 21 intersects the following highways in Jefferson County. Missouri State Route 21, at Hillsboro.
