Great Sand Dunes National Monument
Great Sand Dunes National Monument in south-central Colorado contains some of the largest and highest dunes in the United States. Established in 1932, the monument covers an area of 38,662 acres. Formed by the continuously blowing southwesterly winds that pick up sand from the arid San Luis Valley, the sand dunes rise at the base of the western slope of the Sangre de Cristo Mountains in the San Juan Valley. The windswept dunes, which can shift as much as 7 feet in one day, are visible for about 70 miles.
United States National Park Service: Great Sand Dunes National Monument, Colorado
Browse site description and visitor information plus profiles the area's wildlife, hydrology, geology, and history.
United States National Park Service: Great Sand Dunes National Monument, Colorado: Geology
View a presentation on the geology of the Great Sand Dunes National Monument in Colorado at this site from the U.S. National Park Service.