The Land Itself, Glaciers, Dunes, and the Shape of Indiana

Indiana is a state of geological contrasts that most people drive through without registering. The flat, almost featureless midsection, where a long drive north from Indianapolis to the Michigan line feels like sailing across a slow green sea, is the product of the Wisconsin glaciation, which reached its maximum extent here roughly twenty thousand years ago and retreated about fourteen thousand years ago. The glacier flattened the terrain, scraped away hills, deposited till, and left behind a landscape so level that the pioneers who first saw it thought they had found the richest soil on earth.

They were right. In the south, below the glacial margin, the landscape is entirely different. The unglaciated hills of the Hoosier National Forest ripple through Brown and Monroe and Orange counties like a rumpled blanket, steeper, less fertile, more wooded.

Brown County in particular became, in the early twentieth century, a celebrated artist colony precisely because the hills looked nothing like the Indiana most people knew. Covered bridges, narrow valleys, hardwood forests. In autumn the color turns extraordinary.

Then there is the north shore. The Indiana Dunes along the Lake Michigan shoreline are among the most ecologically diverse landscapes in the eastern United States, a narrow band where boreal plants from the north, prairie plants from the west, and Eastern deciduous forest species all meet within a few miles. The dunes themselves are active, still being shaped by lake winds, some reaching heights of over one hundred feet.

The Indiana Dunes National Park, established in twenty nineteen after decades as a state and national lakeshore, protects fifteen thousand acres of this improbable coastline. Henry Chandler Cowles, the botanist who pioneered the science of plant succession, did his foundational work on these dunes in the early nineteen hundreds. The dunes became a textbook before they became a park.