Nebraska Sandhills: Western Hemisphere's Largest Dune System Captured by NASA

The Nebraska Sandhills, stretching across about 20,000 square miles (52,000 square kilometers) in the north-central part of the state, are recognized as the largest system of sand dunes in the Western Hemisphere. This expansive, undulating landscape was captured in an image on August 19, 2025, by the Operational Land Imager (OLI) on NASA's Landsat 8 satellite.

Grasslands cover these rolling hills, providing crucial grazing grounds for livestock. The landscape is also dotted with lakes and wetlands, which collectively support a diverse array of plant and animal species.

The geological formation of the Sandhills began with sand originating in the Rocky Mountains. Rivers transported this eroded material, depositing it across the Great Plains during the Pleistocene epoch. During subsequent periods of drought, winds, primarily from the north or south, lifted sand from dried riverbeds, gradually building and shaping the dunes. The stabilization of these features by grassland vegetation occurred approximately 3,500 years ago.

Some of the most prominent dunes, located in the northwestern part of the region, can reach heights of up to 400 feet (120 meters) and extend for several miles. These transverse dunes typically exhibit gentler northern slopes, indicative of the dominant influence of northerly winds. In other areas, dunes display more symmetric profiles, suggesting that winds blew with nearly equal strength from both the north and south, alternating with the seasons.

Today, the grasslands serve as essential pastureland for grazing livestock. Ranching significantly expanded in the area following the Kinkaid Act in 1904, which allotted 640-acre parcels to settlers. The region now hosts a larger population of cattle than humans, with the Sandhills encompassing half of Nebraska’s nearly 23 million acres of rangeland and pastureland. Some ranchers employ grazing patterns that emulate the historical movements of bison herds.

Protected public lands are also found within the Sandhills, including the Crescent Lake National Wildlife Refuge on its southwestern edge. This refuge contains wetlands, such as shallow lakes, marshes, and wet meadows, which occupy the valleys between dunes. The land here is highly permeable, allowing precipitation to seep down and recharge groundwater rather than flowing through stream channels. Situated along the Central Flyway, the refuge is a vital haven for migratory birds, supporting dozens of species of waterfowl, marsh birds, and shorebirds, alongside various types of turtles.

According to NASA Breaking News, the Nebraska Sandhills represent a significant natural feature that continues to be observed and studied.