Spring Lake is located in central Illinois in Tazewell County 25 miles southwest of Peoria. It is a 1,285-acre impound and is 8.5 miles long and roughly parallels the east side of the Illinois River.
The lake was formed as a "meander" of the river with dykes being built beginning in 1903. In 1950, the dyke levels were raised allowing the lake to inundate Saiwell Lake and doubling the size of the original. The new lake reached its capcity in 1960.