Spring Lake State Fish and Wildlife Area in southwestern Tazewell County near Manito is a 2,032-acre Illinois park and wildlife management area centered on a long, shallow alluvial lake beside the Illinois River. Reshaped by dike construction in the 1900s and 1950s, it now includes the former Spring and Saiwell lakes as the two halves of the modern lake. Unusual for Illinois, it supports rich aquatic vegetation, spring-fed cold water, and one of the few remaining upland pine forests along the river. Managed for fishing, birdlife, hunting, boating, hiking, and camping, it is also important for muskie propagation and wetland habitat conservation.