Places We Protect

Olin Lake


Olin Lake
Olin Lake Nature Preserve Located in Lagrange County, Indiana. © Laura Sertic/TNC

Olin Lake is the largest lake in Indiana with an entirely undeveloped shoreline.



Why You Should Visit

Nowhere else in the state can outdoor enthusiasts find a waterway as large as Olin Lake in Lagrange County with barely a hint of human intervention and development. The crystal clear waters are surrounded by trees and dense vegetation, with tamaracks turning the landscape a smoky gold in the autumn months. Come spring, the forest floor is painted with splashes of color by native wildflowers. Whether hiking the 1.5 miles of walking trails or launching your canoe down nearby Oliver Lake, this natural area is a sight to see.

Olin Lake was dedicated as a State Nature Preserve in 1975-6 and 1989. It is owned and managed by the Indiana Division of Nature Preserves. Work done here is in partnership with ACRES Land Trust, Indiana Heritage Trust, and Olin Lake Home Owners Association.

Conservation Concerns

The state-threatened early ladies' tresses and the rare alder buckthorn can be found around Olin Lake. A small, native population of the rare cisco—or lake herring—also inhabits the cool, deep waters. Please be careful of these sensitive species while walking around or boating in Olin Lake.




341 acres

Explore our work in this region

What to See: Plants and Animals

Tamarack and yellow birch grow along the low, marshy border with other uncommon plants such as winterberry, poison sumac, buttonbush, and dwarf birch. Aquatic vegetation is sparse because the lake bottom is covered with marl, a white calcareous substance precipitated from the water. Near the south shore is a swampy, hourglass-shaped island. Large specimens of sugar maple, beech, hackberry, and red oak can be found on the upland portion of the southeast shore.

Wildflowers begin to cover the forest floor in early spring. Skunk cabbage shows itself first and abounds in the low, mucky spots. Trout lilies, Dutchman's breeches, celandine poppies, and Jack-in-the-pulpit paint the forest floor. State-threatened early ladies' tresses and the rare alder buckthorn also occur on the property.

The lake is best seen by boat, but there are trails available for woodland hiking. One of these trails ends at the lake's edge for a beautiful scenic view. Boats may NOT be launched at the lake; public access is provided on nearby Oliver Lake with access to Olin Lake available through a connecting channel.

For More Information

IDNR's Division of Nature Preserves