The Saginaw and Mount Pleasant Railroad was a wholly owned subsidiary of the Flint and Pere Marquette Railroad (F&PM). It was established to construct a railway line from a junction with the F&PM main line at Coleman, Michigan, to Mount Pleasant, Michigan. The line opened on December 15, 1879, as a narrow gauge line. In mid-1884 the line was converted to . On January 31, 1889 the company was formally merged into the F&PM along with the East Saginaw and St. Clair Railroad, the Saginaw and Clare County Railroad, and the Manistee Railroad.
In 1979 the C&O abandoned the line.