The Nebraska Sand Hills is a unique region in north-central Nebraska, characterized by rolling sand dunes covered with grass and wildflowers. This area spans approximately 19,300 square miles, making it one of the largest sand dune formations in the United States. The dunes were formed by wind-blown sand from ancient riverbeds and are home to diverse ecosystems. The Sand Hills are primarily used for ranching and are known for their rich biodiversity, including various species of birds and mammals. The region's sandy soil supports a variety of grasses, which are crucial for grazing livestock. The Sand Hills also play a significant role in the local water supply, as they help recharge the aquifers beneath them.