Mount Pleasant, city (1990 pop. 23,285), seat of Isabella co., central Mich., on the Chippewa River; settled before 1860, inc. as a city 1889. The city grew after oil was found nearby in 1928. Oil wells and refineries are there, and machinery is manufactured. Mount Pleasant is the seat of Central Michigan Univ. The Saginaw Chippewa reservation, with a casino and resort, is to the east.