2013
San Luis Valley — 8,000 sq. miles, averaging 7,600′ elevation — is the largest high desert valley in North America. Situated in south central Colorado, with a small portion extending south into central New Mexico, this gradually-sloping, 122 mile long north-to-south flat basin, 74 miles wide, separates Colorado’s two largest mountain ranges – the San Juans to the west, and the Sangre de Cristos to the east.
As part of the Rio Grande Rift, San Luis Valley extends east from the Continental Divide. The Rio Grande River rises out of the eastern San Juan Mountains and flows south into New Mexico; Colorado rivers west of the Continental Divide are drained by the Colorado River. Receiving little precipitation, the San Luis Valley is comprised of desert lands; with no clear southern boundary, it is generally considered to include the San Luis Hills of southern Colorado and the Taos Plateau of northern New Mexico.
Along the eastern edge of San Luis Valley are two significant features:
Blanca Peak, at 14,351′, is the fourth highest mountain in Colorado, and the highest peak in the Sangre de Cristo Mountains. Situated at the southern end of the more extensive Sangre de Cristo Range, it is the highest peak in both ranges, and is located 20 miles east-northeast of the town of Alamosa. Blanca Peak is also the highest point of the entire drainage basin of the Rio Grande, and is higher than any point in the U.S. east of its longitude.
Fifteen miles northwest of Blanca Peak, the Great Sand Dunes National Park and Preserve is situated in the lee of the Sangre de Cristos. These sand dunes, reaching as high as 750′, are the highest in North America.
