Red River Valley

The Red River Valley is a broad, remarkably flat lowland straddling the border of Minnesota and North Dakota in the United States and extending north into Manitoba, Canada, centered on the northward flowing Red River of the North. It occupies the former bed of glacial Lake Agassiz, an ice age lake whose fine silts and clays were laid down across the basin as the lake drained, and those lake bottom sediments now form one of the flattest stretches of land on Earth, roughly 9,300 years old. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/