Weidman is an unincorporated community in Isabella County in the U.S. state of Michigan. It is a census-designated place (CDP) for statistical purposes, but had no independent municipal authority. The population of the CDP was 879 at the 2000 census.
The community is situated on the boundary between Nottawa Township on the east and Sherman Township on the west. The area of the CDP within Sherman Township is somewhat larger than that within Nottawa Township. The Nottawa Township section, in addition, lies on part of the Isabella Indian Reservation. While the statistical area has boundaries defined by the U.S. Census Bureau, there are no precise boundaries for the corresponding community. The postal delivery area for the Weidman ZIP code, 48893, is much larger than the CDP, including large portions of both Sherman and Nottawa townships as well as portions of Coldwater and Gilmore townships on the north and Broomfield and Deerfield townships on the south, as well as the village of Lake Isabella and the western half of the community of Beal City.
The main portion of the community is on the south side of the Lake of the Hills, formed by a dam on the Coldwater River. It is at 43°41′15″N 84°58′08″W / 43.6875°N 84.96889°W / 43.6875; -84.96889. The FIPS place code is 85140 and the elevation is 892 feet (272 m) above sea level.