The park rests on a heavily forested valley, up to 250 feet (76 m) deep in places, amidst the farmland of southeastern Minnesota.

Whereas most of the Midwestern United States was blanketed with till, or drift, by three successive ice ages, the Driftless Area remained ice-free.

Therefore, streams and rivers have had a longer time to cut into their beds, eroding deep valleys and leaving high ridges.

Mammals that roam here are raccoons, deer, badgers, minks, beavers, gray and red foxes, muskrats, and wild turkeys.

[2] Europeans began homesteading the area in the 1850s, attracted by rich farming soil, hardwood lumber, and streams conducive to milling.

[7] A small Works Progress Administration crew arrived in 1938 and built the entrance road, flood control structures, picnic ground, and trails.

In the face of anti-expansion sentiment, the 1978 state legislature redrew the statutory boundaries of the park to include only state-owned land.

To improve the habitat for large trout, fisheries staff were setting rocks along the banks of the creek to prevent erosion and create overhangs where the fish could hide.

However Louisiana waterthrushes and sometimes cerulean warblers nest at the base of creekside trees, some of which were being removed to make space for the rocks.