Location: Defiance Lake is a natural lake in Moraine Hills State Park, which is located three miles south of McHenry off of River Road between Illinois Route 120 and 176 in McHenry County.

Description: Defiance Lake is one of a handful of natural glacial lakes in Illinois that has remained relatively undeveloped. Its maximum depth is 18 feet. The lake stays fairly clear for most of the year, but vegetation does become quite thick. Treatment of vegetation is not an option due to threatened plant species. There is no boat launch at the lake, but carry-in boats/canoes/kayaks are allowed. Rental boats are available. Bank fishing is prohibited due to hazardous peat soils that surround the lake, except for designated piers along the boardwalk.

History and Status of the Sport Fishery: Defiance Lake is stocked annually with largemouth bass and channel catfish. The lake is surveyed by IDNR every two years and supplemental sampling for northern pike occurs when conditions allow. Defiance Lake is difficult to sample effectively with electrofishing gear as the vegetation becomes very thick early in the year. Due to this reason, catch rates for most species are low. While abundance may be underestimated, species richness seems to be pretty consistent throughout the years. Defiance Lake should provide something for the angler who wants to catch something other than bass and bluegill as overall, it is a year-round productive and diverse lake that offers a chance to see some uncommon fish species: captured in 2018 were brown bullhead, bowfin, yellow perch, grass pickerel, common carp and pumpkinseed. Previous surveys have shown black crappie, black bullhead, brook silverside, central mudminnow, golden shiner, green sunfish, lake chubsucker, longnose gar, warmouth and yellow bullhead to be present in Defiance Lake.


Fish attractors were installed and fish have been observed using them. Three attractors have been placed and can be seen on the map here: https://www.ifishillinois.org/big_maps/00067.pdf.

Additional Lake Information: Anglers may use no more than two lines or poles when fishing at Defiance Lake. Rental boats are available. Carry-in canoes and kayaks may be launched at the boat ramp located behind the office. Bank fishing is prohibited due to hazardous peat soils that surround the lake, except for designated piers along the boardwalk. Note that piers quickly become surrounded by dense aquatic vegetation during summer months and vegetation treatment is not an option at this lake due to the presence of rare and sensitive plant species. Electric trolling motors are allowed.

Contact Information:
Moraine Hills State Park
815-385-1624
IDNR Fisheries Biologist, Andy Plauck
815-675-2386 ext. 214