Largest lakes & reservoirs in Illinois by acres
There is no widely-accepted minimum surface area that defines a lake. What LakeLubbers describes as a lake, you might call a pond. Acreage of a lake (or sometimes square kilometers) is most often measured at the top surface area when the lake is at normal elevation. The surface area can be considerably smaller or larger when lake levels are lower or higher than normal. North America’s Lake Superior is the world’s largest freshwater lake by this measure.The other measure of a lake’s size is the lake’s water volume. By that measure, the world’s largest freshwater lake is Lake Baikal in Siberia.
You can find many of the world’s largest lakes (acres) on LakeLubbers in the comparison table below. Note: For some lakes, "Largest Lakes - Acres" data is unknown or does not apply, so you may see fewer lakes than the total 64 articles we have published for Illinois lakes.
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Below are lakes within USA > US Midwest Region > Illinois > Compared by surface area in acres. This list does not represent all lakes in Illinois, only the 64 Illinois lake articles we have published on the LakeLubbers website.
Lake name ![]() |
Surface area in acres ![]() |
Lake description |
---|---|---|
Fox Lake, IL (Chicagoland Region, IL, Illinois, US Midwest Region, USA) |
1,881 ac | Also known as Nippersink Lake, Fox Chain O'Lakes Located north of Chicago in the Chicagoland Region of Illinois, Fox Lake is part of the Fox River Chain of Lakes. The Fox River Chain consists of nine … |
Cedar Lake, IL (Illinois, Southern Illinois, US Midwest Region, USA) |
1,750 ac | Cedar Lake is located at the edge of the Shawnee National Forest in southern Illinois. This 1,750-acre reservoir was created by the City of Carbondale … |
Pistakee Lake (Chicagoland Region, IL, Illinois, US Midwest Region, USA) |
1,716 ac | Also known as Lake Pistakee, Fox Chain O'Lakes Pistakee Lake is a well-known destination to generations of Chicago area Lakelubbers. Located on the famous Fox River Chain of Lakes in the Chicagolan … |
Grass Lake, IL (Chicagoland Region, IL, Illinois, US Midwest Region, USA) |
1,360 ac | Also known as Fox Chain O'Lakes Grass Lake is one of nine lakes linked by channels to form the Fox Chain O’Lakes in northern Illinois. The combination of lakes is the largest inland, … |
Lake Taylorville, IL (Central Illinois, Illinois, US Midwest Region, USA) |
1,286 ac | Completed in 1962 by the City of Taylorville, Illinois, Lake Taylorville is the city’s source of water and a major recreation facility. The reservoir … |
Lake Lou Yaeger (Central Illinois, Illinois, US Midwest Region, USA) |
1,269 ac | Also known as Lake Lou, Lou Yaeger Reservoir One of the hidden gems in the central Illinois heartland, Lake Lou Yaeger provides over 1200 acres of recreational enjoyment to residents and visitors … |
Lake Glenn Shoals, IL (Central Illinois, Illinois, US Midwest Region, USA) |
1,250 ac | Also known as Glenn Shoals Lake Lake Glenn Shoals, also known as Glenn Shoals Lake, is located near Hillsboro, Illinois. The City of Hillsboro built the lake for flood control and wa … |
Lake Mattoon, IL (Central Illinois, Illinois, US Midwest Region, USA) |
1,065 ac | Surrounded by farmlands in the Central region of Illinois is Lake Mattoon. A quiet and tranquil retreat for many Illinoisans and out-of-towners, the l … |
Little Grassy Lake, IL (Illinois, Southern Illinois, US Midwest Region, USA) |
1,000 ac | Surrounded by watchful forest trees and open grasslands, the Little Grassy Lake is a quiet body of water sitting in the middle of a Southern Illinois … |
East Fork Lake, IL (Illinois, Southern Illinois, US Midwest Region, USA) |
934 ac | Also known as East Fork Reservoir East Fork Lake, in the Southern Region of Illinois, is a well-kept secret in a land of many secrets. The southern third of Illinois has been known as … |
Wolf Lake, IL/IN (Chicagoland Region, IL, Illinois, Indiana, North Indiana, US Midwest Region, USA) |
907 ac | With Chicago, Illinois on one side and Hammond, Indiana on the other, Wolf Lake is a pocket of green offering respite to the weary city dweller. The w … |
Evergreen Lake (Central Illinois, Illinois, US Midwest Region, USA) |
900 ac | Also known as Evergreen Reservoir One of Central Illinois’ best-kept secret lies just north of Bloomington: Evergreen Lake. When the growing city needed additional water supply in 1971 … |