<P> The Herard family--after whom Mount Herard is named--established a ranch and homestead along Medano Creek in 1875, using the old Medano Pass Road to travel to and from their home . The modern unpaved road follows the old route and is open only to four - wheel drive, high - clearance vehicles as it passes through deep sand, rises to Medano Pass, and continues east into the Wet Mountain Valley . The Herards grazed and bred cattle in the mountain meadows, raised horses, and established a trout hatchery in the stream . Other families homesteaded near the dunes as well, including the Teofilo Trujillo family whose sheep and cattle ranch in the valley later became part of the Medano--Zapata Ranch, owned by the Nature Conservancy since 1999 . The Trujillo's extant homestead and the ruins of a destroyed one were declared a National Historic Landmark in 2004 . Frank and Virginia Wellington built a cabin and hand - dug the irrigation ditch that parallels Wellington Ditch Trail located south of the park campground . </P> <P> Gold and silver rushes occurred around the Rockies after 1853, bringing miners by the thousands into the state and stimulating mining businesses that are still in operation . Numerous small strikes occurred in the mountains around the San Luis Valley . People had frequently speculated that gold might be present in the Great Sand Dunes, and local newspapers ran articles in the 1920s estimating its worth at anywhere from 17 cents / ton to $3 / ton . Active placer mining operations sprang up along Medano Creek, and in 1932 the Volcanic Mining Company established a gold mill designed to recover gold from the sand . Although minute quantities of gold were recovered, the technique was too labor - intensive, the stream too seasonal, and the pay - out too small to support any business for long . </P> <P> The idea that the dunes could be destroyed by gold mining or concrete manufacturing alarmed residents of Alamosa and Monte Vista . By the 1920s, the dunes had become a source of pride for local people, and a potential source of tourist dollars for local businesses . Members of the P.E.O. Sisterhood sponsored a bill to Congress asking for national monument status for Great Sand Dunes . Widely supported by local people, the bill was signed into law in 1932 by President Herbert Hoover . Similar support in the late 1990s resulted in the monument's expansion into a national park and preserve in 2000 - 2004 . </P> <P> The park contains the tallest sand dunes in North America, rising to a maximum height of 750 feet (229 m) from the floor of the San Luis Valley on the western base of the Sangre de Cristo Range . The dunes cover an area of about 30 sq mi (78 km) and are estimated to contain over 5 billion cubic meters of sand . </P>

When did the great sand dunes become a national park