Weidman is an unincorporated community in Isabella County, Michigan, United States. It is a census-designated place (CDP) for statistical purposes, but has no independent municipal authority. The population of the CDP was 959 at the 2010 census, up from 879 at the 2000 census.

According to the United States Census Bureau, the CDP has a total area of 5.9 square miles (15.4 km), of which 5.6 square miles (14.6 km²) are estate and 0.3 square miles (0.8 km), or 4.98%, are water. The built-up middle of town is in the southern ration of the CDP, on the south side of Lake of the Hills on the Coldwater River. The Coldwater is a south-flowing tributary of the Chippewa River and so part of the Saginaw River drainage basin.

Weidman is 16 miles (26 km) by road northwest of Mount Pleasant, the Isabella County seat, and 19 miles (31 km) southwest of Clare.

The community is situated upon the boundary in the midst of Nottawa Township upon 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 upon part of the Isabella Indian Reservation. While the CDP has boundaries defined by the U.S. Census Bureau, there are no perfect 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 competently as portions of Coldwater and Gilmore townships upon the north and Broomfield and Deerfield townships upon the south, as well as the village of Lake Isabella and the western half of the community of Beal City.