Trail Landscape

Two Miles Thick!
The Ice Age had a profound impact on the world. During the past 2.5 million years, colossal ice sheets repeatedly gripped the globe — perhaps 15 times. Glaciers sculpted, as if by the hand of a potter, about one-third of the earth's landmass. It's hard to imagine the immensity of Ice Age continental glaciers. Sometimes two miles thick, they stretched from today’s Long Island, New York, to Montana, and from Ohio to Hudson Bay, Canada. The mountain glaciers we see today in Alaska or the Swiss Alps are tiny by comparison.

Wisconsin is the best place to witness many of the landforms created by continental glaciation. Fittingly, the most recent period of the Ice Age, which slowly ended only about 10,000 years ago, is known as the Wisconsin Glaciation.

Near the end of the Wisconsin Glaciation, a series of ridges formed between two immense lobes of glacial ice in what is now southeastern Wisconsin. These ridges are 120 miles long. Scattered among them, areas of crater- or kettle-like depressions were created by large chunks of melting ice. Geologists named this region the Kettle Moraine. Studies that began in the Kettle Moraine during the 1870s led to key discoveries and the first map of the extent of continental glaciation in North America.

The Ice Age further left its mark on the world's plants, animals and even its people. The ranges of all species were compressed toward the equator and then expanded as the great ice sheets melted northward. According to a 1995 Wisconsin Department of Natural Resources report, "The greatest historical event impacting Wisconsin vegetation occurred 10,000-60,000 years ago when Wisconsin was invaded by continental ice sheets." Huge, now-extinct beasts, such as mammoth and mastodon, roamed areas near the glacial ice. Some anthropologists speculate that humans would not have evolved to our present state without the challenges posed during the Wisconsin Glaciation.

Along the Trail of the Ice Age
A walk on the Ice Age Trail today has its challenges, but is considered leisurely by most amblers. The majority walks segments of the Trail for short periods of time — a day here, a day there. More than 30 people have hiked the entire Trail, and several have thru-hiked (hiked from one end of the trail to the other in a single, continuous journey).

Perhaps the greatest challenge facing us today is actually finishing the Ice Age Trail. About half of the thousand-mile route is complete. Anyone thinking about hiking the entire Trail needs to plan on walking along a number of roads to connect the off-road segments. But the Ice Age Park & Trail Foundation and its partner organizations slowly continue to acquire lands, and volunteers keep busy building the new segments necessary to fill in the gaps.

Like the 80-year effort to finish the Appalachian Trail, we are confident that the Ice Age Trail will be completed.

The Route
The Ice Age Trail courses like a river for a thousand miles through a varied landscape. Walk the Ice Age Trail to witness hundreds of crystal lakes and thriving prairies, productive farmlands, towering white pines and diverse wetlands, ancient Native American effigy mounds, remnant oak savannas, charming cities and many of the world's finest examples of the effects of continental glaciation. The basic features defining the route of the Ice Age Trail are the Kettle Moraine of eastern Wisconsin and extending westward along the most-recent terminal moraine. Geologic features along the route include: kames, lakes, drumlins, ice-walled-lake plains, outwash plains, eskers, tunnel channels, unglaciated features of the Driftless Area and other older landforms.

A Walk Through Time
The Ice Age Trail primarily interprets the story of continental glaciation. But the geologic story of the Trail goes back much farther. As you walk the Ice Age Trail, your footsteps will take you back in time almost two billion years.

Timepieces you will see along the Ice Age Trail:

• Recent glacially deposited soil, gravel and boulders found in areas of almost every county along the Trail — deposited between 10,000 and 25,000 years ago during the late Wisconsin Glaciation.

• Areas along the Trail covered by earlier continental glaciations in Green County and parts of western Rock, southern Dane and Marathon counties — between 25,000 and 2,500,000 years ago.

• Dolomite of the Niagara Escarpment in Door County — between 410 million and 440 million years old.

• Sandstone rock outcrops of Green, Rock, Dane, Columbia, Sauk and Adams counties — between 460 million and 550 million years old.

• Basalt bluffs and exposures of Polk County — 1.1 billion years old.

• Quartzite of the Baraboo Hills (Sauk County) and Blue Hills (Barron and Rusk counties) — 1.6 billion years old.
  
• Rock outcrops at Grandfather Falls, Lincoln County, and Eau Claire Dells (mylonite), Marathon County —1.8 billion years old.