Michigan State Route 21 runs east-west in Northern Clinton County. It goes from the Clinton/Ionia County Line, near Pewamo, to the Clinton/Shiawassee County Line, at Ovid. MI St Rt 21 passes throught the following towns in Clinton County. Fowler St. Johns
Ovid MI St Rt 21 is not multi-plexed in Clinton County. MI St Rt 21 intersects the following highways in Clinton County. BUSN U.S. Rt. 127, at St. Johns.
WB MI St Rt 21 near Spring Street in St. Johns. WB MI St Rt 21 west of BUSN U.S. Rt. 127. A junction marker on SB BUSN U.S. Rt. 127. EB MI St Rt 21 at BUSN U.S. Rt. 127. EB MI St Rt 21 east of BUSN U.S. Rt. 127. EB MI St Rt 21 east of St. Johns. EB MI St Rt 21 at U.S. Rt. 127.
