Loma Prieta (from Spanish loma -hill, prieta -dark) is a Northern California mountain in the Santa Cruz Mountains. The peak is on private property about 11 miles (18 km) west of Morgan Hill in Santa Clara County. The dirt road to the summit is gated, but the tower maintainers generally do not mind hikers.
A rural area south and east of the summit is sometimes referred to as Casa Loma, named for an unpaved road through the area. The name is unofficial but its use is supported by the existence of a Casa Loma Volunteer Fire Department in the area. Loma Chiquita Road also serves this general area near the Santa Cruz County line.
From 1976 through 1990 amateur astronomer Donald Machholz set up his telescope an average of 120 times a year on the south slope of this mountain to search for comets. From this site he discovered three new comets that bear his name, including Periodic Comet Machholz 1 96P/Machholz on May 12, 1986.
The first official West Coast Messier Marathon was conducted from this site in March 1979.
The 1989 epicenter of the Loma Prieta earthquake was near the mountain.
The mountain was the longtime site for the transmitter tower of San Jose television station KNTV (from 1955 to 2005). It moved its transmitter to San Bruno Mountain in September 2005, after it became the Bay Area's NBC affiliate.
Loma Prieta is the tallest peak in the Santa Cruz Mountains.