Olin Lake Nature Preserve

Olin Lake Nature Preserve is the largest undeveloped lake in Indiana. The water is remarkably clear. Over the years, calcium precipitating from the lake’s water formed a white substance called marl that now coats the bottom of the lake.

Olin Lake

Marl is a mixture of calcium carbonate, clays, and sediments that inhibits the growth of many aquatic plant species; the lack of vegetation and its decay products is a major reason why the water is so clear.

Also striking is the previously mentioned lack of development. You may see a boat or two, as a short channel connects Olin Lake to the larger (and developed) Oliver Lake, but generally the prospect is undisturbed by motors, people, or buildings.


Upland portions are rich with large-flowered trillium and other spring wildflowers, while thick stands of skunk cabbage will cover most lower, wetter spots as the year advances.

The southeast portion of the preserve – Browand Woods - is accessible through the far trail loop, but because most visitors go straight to the lake and return, this area receives relatively little attention. Selective logging of several valuable species in the late 1960s considerably thinned the woods, but some of the less commercial species have since filled in gaps between stumps.

Large maples and oaks are still present, but beech trees seem especially prominent, both because of their size and because their strikingly smooth trunks make them stand out from other species. Indiana’s lake country has many natural attractions, but this is among the best.


A figure eight trail heads east from the parking area. Sign in at the registration box and, if available, pick up a brochure. Because large areas adjacent to the lake are wet, the trail stays well away from the water’s edge over most of its tread. However, a short spur does extend to the shoreline over a rather wobbly collection of objects that, with a little luck, will keep your feet dry.


Lagrange County. From Wolcottville, north 2.0 miles on State Road 9, then left 1.75 miles on 600 South until it ends in a “T” at 125E, then right on 125E 0.5 miles to the parking area on the right.

North 41 33.718 West 85 24.038
DeLorme 22:D5

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Nearby Natural Areas

Lonidaw Nature Preserve
Maplewood Nature Preserve
Spurgeon Nature Preserve


Bloom: Hiking Indiana; Page 44
Habeck: Wild Indiana; Page 36
Indiana Department of Natural Resources
McPherson: Indiana Best Hikes; Page 32
Nature Conservancy: Guide to Indiana Preserves; Page 172