Walking the Edge of the Last Glacier
Near Baraboo, Wisconsin
Imagine a wall of ice two miles high advancing across the continent, grinding, pressing, rearranging the landscape as it moved. Then imagine it pausing, melting, pulling back, and leaving behind a record of exactly where it stopped. That record runs more than a thousand miles across Wisconsin, and the Ice Age Trail follows it.
The trail traces the terminal and recessional moraines left by the last continental glacier, the Laurentide Ice Sheet, which reached its southern extent across Wisconsin and began retreating roughly fourteen thousand years ago. What it left behind is a remarkably varied glacial landscape: moraines, eskers, kettles, drumlins, kames, erratics, and the Kettle Moraine in southeastern Wisconsin, where two immense lobes of glacial ice converged and created a long ridge, punctuated by the crater-like depressions formed by buried chunks of melting ice.
The idea of connecting these features with a single long trail belonged to a Milwaukee attorney and outdoorsman named Ray Zillmer. In nineteen fifty-eight he founded what is now the Ice Age Trail Alliance to advocate for the concept. The legislation authorizing the Ice Age National Scientific Reserve passed in nineteen sixty-four. Congress designated the Ice Age National Scenic Trail in nineteen eighty, one of only eleven national scenic trails in the United States.
The full trail runs from Saint Croix Falls in the northwest to Potawatomi State Park on the Door Peninsula in the northeast, though not every segment is yet complete. Where it runs through the Baraboo Hills near here, it passes over quartzite outcrops that are roughly one point six billion years old.
Wisconsin carries the marks of glaciation in ridges, kettles, and hollows that reward a long walk.
