Tucked away in the Palos Preserves in southwest Cook County, 372-acre Cranberry Slough Nature Preserve was only the fifth nature preserve in Illinois when it was dedicated in 1965. Distinguished by its peat bog ecosystem cradled by rolling upland woods, the site is a relic of the glacial era and supports habitats uncommon this far south.
Enjoying Cranberry Slough
Cranberry Slough is one of many sloughs in the Palos area. (A slough—pronounced “slew”—is a somewhat colloquial name for a shallow wetland or pond.) To view the slough and surrounding woodlands, visitors can park at the pulloff along 95th Street and head south on the wide, well-maintained yellow trail, a section of the Palos unpaved trail system.
For a longer hike to the slough, visitors can park in the Country Lane Woods lot, which has picnic tables and a shelter, as well as port-o-johns. An old country lane (the preserve’s namesake) now provides a wide gravel path shared by bikers, hikers, skiers and horseback riders through the heart of the preserve. Where the country lane meets the yellow trail, walk east to reach the slough. This route adds about a mile to the adventure, but the hiking is relatively easy.
Cranberry Slough’s trails offer slight yet interesting elevation changes. Both bird- and frog-watchers will want to bring binoculars to spy animals in the trees and water.
Nature at Cranberry Slough
Cranberry Slough Nature Preserve includes one of only a handful of peat bogs in Illinois. A unique ecological community developed in this hollow, formed by an ice block stranded during the retreat of the glacier some 14,000 years ago. Plants such as sphagnum moss, a more typical inhabitant of the cooler climes of Wisconsin, Michigan and Minnesota, share company with familiar prairie and woodland species, such as white wild indigo, marsh blazing star and tall bellflower. Birders can see pileated woodpeckers, eastern bluebirds and tufted titmice, among other species. Year-round access to water makes the slough popular among herons, egrets, ducks, gulls and gadwalls.
In spring and summer, visitors can enjoy serenades from the variety of frogs in and around the slough, including gray tree frogs, spring peepers and green frogs. Beaver and tiger salamanders also make homes in the wet areas.
The low areas around the slough give way to rolling hills and higher, drier ground, where white and black oaks dominate an open woodland. Wildflowers, such as toothwort and spring beauty, blanket these hills among wefts of sedges and grasses in the spring.
Forest Preserves staff and local volunteers conduct ongoing restoration and ecological management work here, including prescribed burns. To join the restoration effort, visit the Forest Preserves’ volunteer page.