On-A-Slant Village: Where the Heart Meets the Missouri

On the sloping bluff where the Heart River flows into the Missouri River, the Mandan built one of the great villages of the Northern Plains. On-A-Slant Village, named for its terrain, was established in the late fifteen hundreds and thrived here for nearly two hundred years. At its peak it held approximately eighty-six earth lodges and a population of one thousand to fifteen hundred people. It was a fortified city, protected by ditches and timber palisades, and it sat at the center of a trade network reaching from the Gulf Coast to Canada.

The Mandan who lived here were master builders. Each earth lodge required about one hundred fifty trees to construct. The framework of cottonwood posts was lashed with willow, covered with grass, and then sealed with earth thick enough to walk on. A hole in the roof let in light and vented smoke. Families kept their best horses inside at night. The lodges lasted a generation and were continuously repaired and replaced.

When Lewis and Clark paddled upriver in the autumn of eighteen oh four, they observed that On-A-Slant was already in ruins. The smallpox epidemic of seventeen eighty-one had struck with devastating force. Survivors fled north to join the Hidatsa near the Knife River. Within two decades the lodges had collapsed into the earth that built them.

U.S. Army surveyors arrived in eighteen seventy-two and built Fort McKeen on the same bluff. The fort was renamed Fort Abraham Lincoln later that year, and six companies of the Seventh Cavalry arrived the following autumn under the command of Lieutenant Colonel George Armstrong Custer.

Today the site is the oldest state park in North Dakota. Six earth lodges have been reconstructed on their original floor plans, and you can walk inside structures nearly identical to those the Mandan built here four centuries ago.