Learn More About Merwin

Landscape and Stewardship

The Merwin Preserve is considered a premier natural area of central Illinois. Wisconsinan-era glaciers helped craft the rolling hills of this site 10-20,000 years ago, leaving behind several unique microenvironments that transition from upland savanna to bottomland forest and dry prairie to damp ravines. The river marks the leading, or southernmost, edge of the El Paso end moraine.

Both the north and west gates lead through one of the finest examples of oak savanna left in the state. This habitat is so rare, in fact, that an Illinois Nature Preserve designation protects 35 acres of this savanna and a small hill prairie on the river bluff into perpetuity. Besides prairie, this was the most common scene found by the first European settlers as natural fire kept the understory open. Today, we minimize woody undergrowth with prescribed fire and removal by hand.

"Among the 'oak-openings' you find some of the most lovely landscapes of the West, and travel for miles and miles through varied park scenery of natural growth, with all the diversity of gently swelling hill and dale - here, trees grouped, or standing single - and there, arranged in long avenues as though by human hands, with slips of open meadow between.  Whenever a few years elapse without the [fire] touching a district, the thick sown seeds of the slumbering forest, with which the rich vegetable mould... spring up from the green sod of the country."

- C.J. Larobe, traveling in the Midwest, The Rambler in North America, 1835

Six species of oak are found in the preserve, with white and bur being most common throughout the uplands. Do not miss the signature white oak that stretches from the crest of the north river bluff trail. Sycamores and cottonwoods anchor the meandering river bottoms. The preserve is popular in fall as dense canopies show off colorful foliage.

The prairies, savannas, and bottom lands are all home to an array of plant species that provide year-round interest. A whimsical carpet of Virginia Bluebells also attracts many visitors each spring. The shooting star wildflower is found here, along with numerous woodland spring ephemerals such as red trillium, white trout lily, Jacob’s ladder, and wild columbine. Hillside seep marshes on either side of the river provide habitat for sedges, mosses, liverworts, and the rare marsh marigold.


Several large mammal species are commonly observed year-round such as white-tailed deer and red fox. Keep a close eye out for evidence of warier species that call the river banks home, including beavers, mink, and reintroduced river otters. Several species of freshwater mussels are also found here.

Be sure to bring your binoculars because the Merwin Preserve is a popular stop for local birdwatchers. As many as 160 species of birds have been recorded in and around the preserve. Effective habitat management attracts several popular cavity-nesting species such as red-headed woodpecker, northern flicker, eastern bluebird, and white-breasted nuthatch. Dead trees intentionally left standing throughout the preserve – called snags – serve as food, shelter, and a great place to observe these species.

Have you wondered about the numbered birdhouses dotting the woodland? They support a long-term study of another cavity nester, the house wren, by Illinois State University, now over 40 years running. Barred owl hoots and spring turkey gobbles are also often heard thundering through Merwin’s river bottoms.

Hiking/Trail Running

Comfortable trails of various length, difficulty, and scenery make this a hiking destination for all interests.  Several features are maintained to make your outing more enjoyable, including memorial benches at scenic overlooks, bridge creek crossings, and stairs to access the north section’s river bottom.

  • West Gate Trail – Take the gentler 1-mile loop past the oak savanna and iconic white oak river bluff overlook, or extend for the full 2-mile undulating loop through the north river bottom.
  • Birkenholz Memorial Trail – This 2.3-mile loop highlights the diversity of the Merwin Preserve as it wanders through hardwood timber, drops into the south river bottom, borders restored prairie, and swings past Rediger pond.
  • Stanley Lantz & John English Trail – Start at the Henline Gate for 1.5 mile out-and-back trip to Lee’s Lookout, or extend further into a block of pine trees popular with owls.



“The opportunity was there, so we went ahead on faith that the community would back us up.”

- John Hodge, 1970 ParkLands board president (Pantagraph)

While the Merwin name reflects the uncle-nephew duo who were among the founding visionaries of the ParkLands Foundation (Loring and Davis U. Merwin), the preserve is an assembly of local legacies pieced together between 1970 and 1994 through a cascade of chance events, generosity, and an energy for conservation that spread like a prairie wildfire.

Lexington-area farmers and outdoor enthusiasts Emile and Viola Rediger long understood the recreational, ecological, and scientific importance of their 107 acres wedged between PJ Keller Memorial Highway and the Mackinaw River.  In 1970, just three years after the founders of ParkLands began to promote the importance of preserving the Mackinaw watershed, the Redigers ignored high-dollar offers from developers to sell what would become the cornerstone at the heart of today’s preserve to ParkLands at less than half its appraised value.

This proved a spark for acquisitions to come.  A second bargain-sale of 130 acres bordering the Rediger tract came courtesy of Lela May Thatcher just a few months later.  Then, in April 1971, a fierce capital campaign crescendoed with a dramatic auction victory of 40 additional adjoining acres from the estate of Harold Gregor, only made possible by local philanthropist Russell Shirk (of Beer Nuts founding fame) and the Shirk Foundation.  This tract was an important victory for public access – today, it serves as the west entrance and canoe launch.

Four more purchases were made between 1974 and 1979 from landowners Herschel Vandegraft, Virgil Stewart, Albert Kinsella, and L.D. Benedict.  A generous estate gift from Towanda resident Leslie Henline funded the 1985 purchase of the 170 acres that became the current southeastern “foot” of the preserve.  Finally, ParkLands ownership became truly contiguous with the 1994 purchase of 40 ecologically-important acres from Illinois Wesleyan University in the heart of today’s preserve.

In 2006, 35 acres of the north bluff became a registered Illinois Nature Preserve primarily due to an extremely rare 11-acre “best of its kind” dry-mesic, black-soil oak savanna and remnants of a glacial drift hill prairie along the steep, southward-facing bluffs above the river.  The remaining 640 acres were permanently designated an Illinois Land and Water Reserve later that year, becoming only one of two ParkLands preserves to carry this protection.  ParkLands also holds a 120-acre private conservation easement adjacent to the preserve’s northeast boundary, ensuring proper management and perpetual conservation of this land.

Active management is a key part of maintaining these habitats.  At the Merwin Preserve (and many ParkLands properties), this includes regular prescribed burnings of prairie and savanna understory, removal of invasive species, and a deer management program.  Routine trail maintenance is also of primary importance at the Merwin Preserve due to its popularity.

The Merwin Preserve remains our most-loved preserve, and yet, even at more than 700 combined acres, accounts for less than 20% of ParkLands-managed properties available to the public.