White Sands National Park is located in Otero and Doña Ana counties, in the state of New Mexico, United States. The park includes a white sand gypsum dunefield which is the largest of its kind on Earth.
As stated in the foundation document:
An island of white within the Chihuahuan Desert, White Sands National Monument provides for and promotes scenic, scientific, and educational opportunities while preserving the world’s largest gypsum dunefield—a dynamic environment created and sustained by wind and water—and protects endemic flora and fauna, unique human and paleontological history, and the quiet solitude of the dunes.