Michigan State Route 51 runs north-south in Western Cass County. It runs from the Cass/Van Buren County Line, near Glenwood, to the Berrien/Cass County Line, near Sumnerville. MI St Rt 51 passes through the following towns in Cass County. Dowagiac
Pokagon Sumnerville MI St Rt 51 is multi-plexed in Cass County. Michigan State Route 62, at Dowagiac.
Branches of MI St Rt 51 in Cass County. SB MI St Rt 51 at the Cass/Van Buren County Line. NB MI St Rt 51 north of MI St Rt 152. NB MI St Rt 51 at MI St Rt 152. NB MI St Rt 51 south of MI St Rt 152. SB MI St Rt 51 south of MI St Rt 152. NB MI St Rt 51 north of Dowagiac. NB MI St Rt 51 near North Street in Dowagiac. A junction marker on WB MI St Rt 62. NB MI St Rt 51/EB MI St Rt 62 at Dowagiac. NB MI St Rt 51 south of Dowagiac. NB MI St Rt 51 north of Sumnerville.
