Alta Loma (Spanish for "Tall Hill") is one of three unincorporated areas that became part of the city of Rancho Cucamonga, California, United States in 1977.
Residents of Alta Loma and Etiwanda finally agreed to incorporation provided their identifying community names would be kept along with separate post offices and ZIP codes.
[5] The Grand Prix fire, which began October 21, 2003, ripped across the mountains just above and, in some places, down into Alta Loma and Etiwanda for six days.
Overgrown brush fueled fire, which ran across the mountain tops and higher foothills to eventually fly into the canyons that are surrounded by homes.
Cucamonga Canyon in particular is a favorite among hikers,[6] although dangerous due to the rough terrain, loose rocks, possible flooding, poison oak, bears, mountain lions, rattlesnakes, bobcats, and other wildlife.