Places We Protect

Big Walnut


A wide, low stream with exposed rocks is flanked by dense forests at Big Walnut Preserve.
Big Walnut Creek Big Walnut Creek runs through Big Walnut Nature Preserve in Putnam County, Indiana. © Timothy Metz

Big Walnut is a large forest that provides extensive habitat for diverse plant life.



Why You Should Visit

Big Walnut Preserve in Putnam County is a dazzling scenic area situated among the rolling hills and steep ravines of Big Walnut Creek Valley. Since being dedicated as a National Natural Landmark in 1985, the preserve has been co-managed by TNC and the Indiana Department of Natural Resources Division of Nature Preserves (DNP). This successful partnership has protected more than 2,400 acres and has ensured the long-term viability of this biologically important natural area.

What The Nature Conservancy is Doing/has Done

Through constructive partnering, TNC and DNP have produced effective management and reforestation efforts in Big Walnut Preserve. Over the past several years, the effort to preserve several thousand contiguous acres of protected interior forests has been accomplished by planting thousands of tree seedlings in old fields and pastures. Both TNC and DNP staff, along with scores of volunteers, have planted more than 125,000 red oak, shellbark hickory, and black walnut seedlings throughout 180 acres of Big Walnut Preserve. In addition, recent land acquisitions have helped to protect local plants, animals, and natural communities, which in turn help to maintain the water quality of Big Walnut Creek.

With DNP managing most of the southern portion and TNC working primarily in the north, both organizations have proved that they can successfully collaborate to manage the site and maximize the integrity of the entire preserve.




Open year-round from dawn to dusk.


2,458 acres

Explore our work in Indiana

What to See: Plants and Animals

With beautiful, glacial-relic stands of eastern hemlock and Canada yew flourishing on cool, north-facing slopes, it’s no surprise that this area was designated as a national natural landmark in 1968. Exceptionally large trees, including the largest known hemlock trees in Indiana, are scattered across the preserve along with one of the few remaining stands of a beech, sugar maple, tulip, poplar climax forest growing in west-central Indiana.

Spring brings a carpet of wildflowers including spring beauties, anemones, Virginia bluebells, and large-flowered trilliums, and the emergence of cerulean, worm-eating and hooded warblers and great blue herons. The rare-plant seekers won't be disappointed at Big Walnut either; eastern hemlock, Canada hew, Clinton's woodfern, Goldie's fern, and bristly sarsaparilla—among other uncommon plants—can be found in this amazing preserve.

Access and Trails

The Tall Timbers Trail is a 2.8-mile loop trail through a portion of the northern part of Big Walnut, including Fortune Woods. It is a moderate hike, with 40+ stairs that traverse a steep ravine. Fortunately, a landing halfway up the stairs and a bench at the top provide resting areas. There are several small stream crossings, so prepare for wet feet. Parking for five vehicles is available at the trailhead.

With support from CenterPoint Energy, TNC was able to partner with the Indiana DNR and the Hoosier Hikers Council to reroute the beginning portion of the Tall Timbers Trail to wind through an amazing part of the preserve. Breathtaking views from the get-go!

The Doyle Trail is a 1.3-mile loop trail through tree plantations that were planted in the early 2000s, many that are now over 10 feet tall. A variety of hardwood tree species were hand planted in what was once row crop fields, including black cherry, black walnut, red oak and white oak. There are two 0.1-mile paths that cut through the outer loop, allowing two options for visitors to shorten the route. The eastern portion of the loop is a moderate hike and offers glimpses of Big Walnut Creek through the trees, while the western portion of the loop stays in the uplands and is an easy hike. The trailhead has a large 12-car parking area almost directly across the road from the Tall Timbers Trail, so why not hike both!

The Rayfield Trail is an out-and-back 2-mile-total route (1 mile in, then 1 mile back). Like the Doyle Trail, it features a tree plantation from the early 2000s. This trail is an easy hike that ends with a great view of Big Walnut Creek. A shorter 0.6-mile alternate loop that meanders through the tree plantation is also an option. This loop branches off to the north of the main trail just before you enter the more mature woods. The trailhead has a small parking area with space for just a few cars.

Here's a map of the Big Walnut Nature Preserve trails.

Check out TNC's Preserve Visitation Guidelines for information regarding your visit to the preserve.

For More Information

Indiana Department of Natural Resources Division of Nature Preserves fact sheet