Andrew and I lived here! White Sands National Monument near Las Cruces, New Mexico; it's called 'monument' instead of park becaue it was created through the Antiquities Act, but it is part of the National Parks Service.
White Sands National Monument in New Mexico. The snow-white dunes of gypsum sand stretch over 275 square miles of desert creating the world's largest gypsum dunefield. Contact me to plan this New Mexico trip!