Missouri Secondary State Route Y is a north-south highway in Southwestern Jefferson County. It runs from Missouri State Route 21, at De Soto, to Missouri State Route 30, near Grubville. MO Sec St Rt Y passes through the following towns in Jefferson County. De Soto Ware Grubville MO Sec St Rt Y is not multi-plexed in Jefferson County. MO Sec St Rt Y intersects the following highways in Jefferson County. Missouri State Route 21, at De Soto.
