DIGITAL SHADED RELIEF
MAP OF THE
COTEAU DES PRAIRIES,
NORTH DAKOTA / SOUTH DAKOTA

This image was produced by TruFlite, using DEM (digital elevation model) data available from the U.S. Geological Survey and other sources.

The view is as if "flying" due southward from the region of Geneseo (Sargent County, N.D.) into South Dakota. A map label for the North Dakota village of "Havana" is visible at the extreme lower-right (i.e. northwest) portion of the image. The dark, reddish line that trends from left to right just south of Havana is the political border between North Dakota and South Dakota.

The Prairie Coteau is one of the most remarkable landforms in North America. Its wedge-shaped tip just cuts northward across the ND / SD state line. The landform itself, although cored by bedrock, largely consists of glacial sediments. Over most of the Coteau, these deposits average >120 m in thickness and in places exceed 200 m. During the last ( = Wisconsinan) glaciation, ice passing southward through the Red River Valley encountered this landform and was split into two lobes: the Des Moines Lobe, which advanced to the southeast and the James Lobe, which advanced to the southwest. Although ice from both lobes overlapped onto the Coteau (leaving prominent moraines), not all of the Coteau was ice-covered during this glaciation.

The southern outlet to Glacial Lake Agassiz is visible as a southward directed, V-shaped depression near the left (east) margin of this image. From here, waters drained southward through a deep valley now partially occupied by Lake Traverse and Big Stone Lake (elongate lakes visible in lowlands toward upper-left of image).

This image is entirely computer-generated, using digital elevation and associated data. The vertical exaggeration is 20X.

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Detail of TruFlite's Prairie Coteau image, in the region of Lake City, South Dakota.

Ray Sterner (Johns Hopkins University) provides a spectacular AVHRR image of South Dakota, with the Prairie Coteau displayed prominently in the northeastern corner of the image. The Black Hills are also visible.

Click here to access Ray Sterner's shaded relief maps for the 50 states.

Click here to access Andrew Birrell's larger scale shaded relief maps of the United States.