The city's elevation is 2,643 ft (806 m) above sea level (as measured at the Tucson International Airport). Tucson is situated on an alluvial plain in the Sonoran desert, surrounded by five minor ranges of mountains: the Santa Catalina Mountains and the Tortolita Mountains to the north, the Santa Rita Mountains to the south, the Rincon Mountains to the east, and the Tucson Mountains to the west. The high point of the Santa Catalina Mountains is 9,157 ft (2,791 m) Mount Lemmon, the southernmost ski destination in the continental U.S., while the Tucson Mountains include 4,687 ft (1,429 m) Wasson Peak. The highest point in the area is Mount Wrightson, found in the Santa Rita Mountains at 9,453 ft (2,881 m) above sea level.