Near Sanger in Oliver County, North Dakota — The American Midwest (Upper Plains)

The Missouri: Origin and History

Photographed by Barry Swackhamer, July 22, 2025

1. The Missouri: Origin and History Marker

Inscription. It begins a mile and a half above the sea in the mountains of southwestern Montana and touches on seven states in its 2,714 mile journey to its junction with the Mississippi River near St. Louis. Its sediment-laden waters gathered from a half million square miles of the heart of the continent, pour into the Mississippi at the average rate of 70,000 cubic feet every second and from there are carried to the Gulf of Mexico.
The Missouri is one of many eastward flowing river systems that formed to drain the Rocky Mountains, and it has probably existed, at least in some ancestral form, ever since the uplift of those mountains some 60 million years ago. United in the Great Ice Ace, though, the Missouri had a much different course, heading northeastward from North Dakota across Canada to the sea (see map). Beginning about two million years ago, a series of great continental ice sheets formed, and expanded southward, they ultimately forced the Missouri into a new path around the southern margin of the ice (see map),

With enormous volumes of glacial meltwater added to its flow, the river quickly cut a new course using

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pre-existing valleys where possible and carving new segments across divides. After glaciation the Missouri River, its old valley filled with glacial sediments, remained in its new southward course.
Today's valley still shows the evidence of these Ice Age events; wide valley segments, such as that south of Bismarck, mark a reused pre-existing valley, while narrower segments such as that south of Washburn record a divide-cut. Steep valley walls and gravel-floored terraces standing high above the floodplain are reminders of the days when the Missouri carried great floods of glacial meltwater.

Topics. This historical marker is listed in these topic lists: Natural Features • Waterways & Vessels.

Location. 47° 12.594′ N, 100° 59.884′ W. Marker is near Sanger, North Dakota, in Oliver County. It can be reached from 22nd Avenue SouthWest (aka River Road) near 16th Street SouthWest. The marker is located in Cross Ranch State Park where the campground fronts the Missouri River. Touch for map. Marker is in this post office area: Center ND 58530, United States of America. Touch for directions.

Regionally,

The Missouri River pre-glacial map image. Click for full size.

Photographed by Barry Swackhamer, July 22, 2025

2. The Missouri River pre-glacial map

this marker is in North Dakota’s Standing Rock Sioux Tribe,

on the Missouri Plateau,

and in Greater Bismarck Area.

It is also in the American Lewis & Clark Corridor,

on the prairies,

and on the Northern Plains.

Globally, it is in North America,

the Western Hemisphere,

the Western World,

and the Anglosphere.

Historically, it finds itself in what was once Rupert’s Land

and also the Louisiana Purchase.

Other nearby markers. At least 8 other markers are within 6 miles of this marker, measured as the crow flies: The Missouri : A Landscape Altered (approx. 0.4 miles away); The Missouri: An Early Highway (approx. ¾ mile away); The Story of Painted Woods (approx. 1.4 miles away); Painted Woods (approx. 1.4 miles away); Cross Ranch (approx. 1.8 miles away); "A Buitifull Countrey" (approx. 1.8 miles away); Soo Line Railroad & Depot (approx. 5½ miles away); Taylor Cabin (approx. 5½ miles away). Touch for a list and map of all markers in Sanger.

The Missouri River, post-glacial map image. Click for full size.

Photographed by Barry Swackhamer, July 22, 2025

3. The Missouri River, post-glacial map

Photographed by Barry Swackhamer, July 22, 2025

4. The Missouri: Origin and History Marker

Credits. This page was last revised on September 27, 2025. It was originally submitted on September 27, 2025, by Barry Swackhamer of Brentwood, California. This page has been viewed 44 times since then and 10 times this year. Photos: 1, 2, 3, 4. submitted on September 27, 2025, by Barry Swackhamer of Brentwood, California.