Skip to main content


Moraine Hills derives its name from a geologic formation known as a moraine, which is an accumulation of boulders, stones and other debris deposited by a glacier. As glacial ice melted here following the Wisconsin glaciation period, it left gravel-rich deposits called kames that make up the park's wooded hills and ridges.

Natural Features

The 48-acre Lake Defiance, located near the center of the park, was formed when a large portion of ice broke away from the main glacier and melted. Lake Defiance is gradually filling in with peat from its marshy shoreline. The lake is one of the few glacial lakes in Illinois that has remained largely undeveloped, maintaining a near-natural condition.

Pike Marsh, a 115-acre area in the southeast corner of the park, is home to many rare plants. Its outer fen area (a very rare marsh wetland) includes Ohio goldenrod, Kalm's lobelia, dwarf birch and hoary willow, while cattails and bulrushes grow in its interior. Pike Marsh also supports one of the state's largest known colonies of pitcher plants, which attract, trap and digest insects.

The 120-acre region known as Leatherleaf Bog is an excellent example of kettle-moraine topography. In geological terms, a kettle is a depression formed when an isolated block of glacial ice melts. The bog consists of a floating mat of sphagnum moss and leatherleaf surrounded by a moat of water. Marsh fern, marsh marigold, St. John's wort and several species of willow put down roots here. Because both Pike Marsh and Leatherleaf Bog are dedicated nature preserves, they are protected by law.

Moraine Hills offers three examples of wetland enhancements. Yellow-head, Black Tern and Opossum Run marshes are samples of what can be accomplished with a little help from man.


For a wide spectrum of wildlife, Moraine Hills is home sweet home. Red fox, coyote, white-tailed deer, eastern cottontail, mink, opossum, and raccoon inhabit the park, while more than 200 species of birds have been identified here. Great blue herons and green herons feed in the marsh areas in the summer, and the park is heavily used by migratory waterfowl, such as mallards, teal, wood ducks and Canada geese.


Fishing is available on both Lake Defiance and on the Fox River. Regulations are posted at both sites. To help preserve the natural state of Lake Defiance, and because of the dangerous peat shoreline, bank fishing is prohibited except from designated piers along the boardwalk. The McHenry Dam area provides access to the Fox River, and a fishing pier accessible to disabled visitors is available.


Archery hunting is available from October 1st - January 16th. For more information please see the Moraine Hill Archery Hunting Information.  

Waterfowl hunting is available at satellite locations of Moraine Hills through the State Lottery system. For more information please see the Black Crown Marsh Site Hunting Information

Shotgun deer hunting is available on the 1,400 acres northeast of River Road during the statewide firearm hunting season. The park is closed to the public and access is limited to permitted hunters only. This takes place each Friday - Sunday the weekend before Thanksgiving, and Thursday - Sunday the weekend after Thanksgiving. For more information, please see the Moraine Hill Hunting Information.


Boat rentals are available for Lake Defiance and the Fox River on a first-come, first-serve basis.  While trailers are prohibited in the park, private boats may be brought in by car top for use on Lake Defiance and the Fox River.  Watercraft must be registered with the state of Illinois.  Electric trolling motors are allowed.  Further information about boat rentals is available by calling (815) 385-5921.


More than 10 miles of trails make Moraine Hills popular for hikers, skiers and cyclists, and provide one of the park's main recreation features. Three trails, surfaced with crushed limestone, wind their way through the park and offer you exceptional scenic and wildlife viewing opportunities. Enjoy the 2-mile Fox River Trail, the 3.2-mile Leatherleaf Bog Trail and the 3.7-mile Lake Defiance Trail. To keep you on track, trails are color coded and one way. A fourth trail, the 1.7 mile River Road trail, is paved.


If your visit to Moraine Hills includes picnicking, you can choose from tables in shaded or open settings throughout the park's 10 day use areas. Each area offers parking, drinking water, and rustic toilet facilities. Flush toilets are available at the McHenry Dam concession building and at the park office. Pike Marsh, Pine Hills, Whitetail Prairie and the Northern Woods day use areas provide picnic shelters. To reserve a shelter visit ExploreMoreIL™.


The park features a conveniently located concession stand at the McHenry Dam.  It provides not only refreshments, bait and tackle, but also boat rentals for both the Fox River and Lake Defiance.  The McHenry Dam Concession is open at 8:00 A.M, 7 days a week from April until October. For more information:  (815) 385-5921.


Artifacts found on the park property indicate human presence in the area within 1,000 years of the retreat of the Wisconsin glacier. Seasonal habitation of the park area extends back to approximately 4,000 B.C. Native American tribes that occupied or passed through the area include the Potawatomi, Sauk, Fox and possibly the Miami and Winnebago. The Sauk and Fox tribes, originally from what is now Canada, claimed ownership of the land at the time of European settlement.

Horace Long was the first known settler in the park area and occupied a portion on what is now the southeast corner of the park. Part of the stone foundation from his cabin still stands along the main park road.

In 1907, the original McHenry dam was built and a hand-operated lock was constructed. The facilities were donated to the people of Illinois in 1924 and construction of a new concrete block dam began in 1934. In the early 1960s, a portion of the park property on the west bank of the Fox River was provided for the locks and managed by the Division of Water Resources.

In 1939, the state of Illinois made the initial McHenry Dam State Park land acquisition 15 acres, on the east bank of the Fox River. Major acquisition of the Lake Defiance area began in 1971, and construction of park facilities took place in the spring of 1975. The present Moraine Hills opened in October 1976.


  • From the North: IL Rt. 12 south to Rt. 176, West on Rt.176 to River Road, North on River Road approx. 2 miles to entrance
  • From the South: IL Rt. 12 north to Rt. 176, West on Rt. 176 to River Road, North on River Road approx. 2 miles to entrance
  • From the East: Rt. 176 to River Road, North on River Road approx. 2 miles to entrance
  • From the West: IL Rt. 176 East to River Road, North on River Road approx. 2 miles to entrance