Great Sand Dunes National Park and Preserve is a national park that conserves an area of large sand dunes up to 750 feet tall on the eastern edge of the San Luis Valley, and an adjacent national preserve located in the Sangre de Cristo Range, in south-central Colorado. The park encompasses 107,342 acres while the preserve protects an additional 41,686 acres for a total of 149,028 acres. It is home to the tallest dunes in North America.