Mount Clemens (klĕmˈənz) [key], city (1990 pop. 18,405), seat of Macomb co., NE of Detroit, SE Mich., on the Clinton River; settled c.1798, inc. as a city 1879. The city is known for its mineral waters. It has a large floral industry and factories that make tool and die equipment, enamels, powder coatings, and tool holders. Nearby is Selfridge Air National Guard Base.