Little Grassy Lake (Illinois)

Little Grassy Lake
Little Grassy Lake
Little Grassy Lake
LocationJackson County, Illinois and Williamson County, Illinois
Coordinates37°38′12″N 89°08′44″W / 37.6368°N 89.1455°W / 37.6368; -89.1455
Typereservoir
Primary inflowsLittle Grassy Creek
Primary outflowsLittle Grassy Creek
Basin countriesUnited States
Max. length4 mi (6.4 km)
Max. width0.5 mi (0.80 km)
Surface area1,200 acres (490 ha)
Shore length136 miles (58 km)
Surface elevation499 ft (152 m)
1 Shore length is not a well-defined measure.

Little Grassy Lake is a 1,200 acres (490 ha) reservoir lakebed in southern Illinois, created by the damming of Little Grassy Creek, a tributary of Crab Orchard Lake and the Big Muddy River. Most of the lake is located in Williamson County, southeast of Carbondale, Illinois. The lake is accessible from Giant City Road out of Carbondale, Illinois. Two arms of the lake penetrate into adjacent Jackson County. The lake is managed by the U.S. Fish and Wildlife Service as part of the Crab Orchard National Wildlife Refuge. As part of a multi-year construction project to repair and replace the Little Grassy Lake dam and spillway, authorities announced plans in 2025 to temporarily drain the lake.