Arroyo Hondo (Santa Clara County)

Calaveras Valley is a valley east of Milpitas, California in the San Francisco Bay Area. It has formed primarily as a result of the actions of the Calaveras Fault. The southern end of the Calaveras Valley is a few miles south of Calaveras Reservoir, while the northern end is at Sunol. See Calaveras Reservoir for more information.

The 2007 Alum Rock earthquake occurred on October 30 at 8:04 p.m. Pacific Daylight Time in Alum Rock Park in San Jose, in the U.S. state of California. It measured 5.6 on the moment magnitude scale and had a maximum Mercalli intensity of VI (Strong). The event was then the largest in the San Francisco Bay Area since the 1989 Loma Prieta earthquake, which measured 6.9 on the moment magnitude scale, but was later surpassed by the 2014 South Napa earthquake. Ground shaking from the Alum Rock quake reached San Francisco and Oakland and other points further north. Sixty thousand felt reports existed far beyond Santa Rosa, as far north as Eugene, Oregon.

Poverty Ridge is a ridge in unincorporated Santa Clara County, California, east of Milpitas. Calaveras Valley lies to its west, while its east side slopes down to meet Arroyo Hondo. Creeks that originate on Poverty Ridge include Calaveras and Penitencia Creeks.

Los Buellis Hills are a short sub−range of hills in the northwestern Diablo Range, in the South Bay region of the San Francisco Bay Area, within Santa Clara County, California.

Calaveras Reservoir is located primarily in Santa Clara County, California, with a small portion and its dam in Alameda County, California. In Spanish, Calaveras means "skulls". The reservoir is fed mainly by Arroyo Hondo and Calaveras Creek. Lying in the Calaveras Valley, the region is geologically active with the Calaveras Fault parallel to and to the west of the dam site. The seismic hazard forced replacement of the original dam. The replacement dam began construction in 2011 and was completed in 2019. The Calaveras Valley has diverse wildlife including deer, coyotes, squirrels, turkey vultures, red-winged blackbirds, yellow-billed magpies, red-tailed hawks, brewer's blackbirds, purple martins, barn swallows, bullock's orioles, and warblers. Since at least 2008, a pair of bald eagles has nested regularly.

Oak Ridge in Santa Clara County, California, is a ridge forming the east canyon wall of Arroyo Hondo, which drains into Calaveras Reservoir. Black Mountain is its highest point. The first known white settlers on Oak Ridge were the Parks family, who ran cattle on the ridge. Now owned by the San Francisco Water Department, the ridge is private property and is off-limits to most people.

Calaveras Creek is a northward-flowing stream in Alameda and Santa Clara counties of California. It runs for 8.5 miles (13.7 km), starting from Poverty Ridge, passing through Calaveras Reservoir, and emptying into Alameda Creek east of Fremont, California. Its main tributary is Arroyo Hondo.

Sierra Vista Open Space Preserve is a 1,678-acre nature preserve in the eastern foothills of Santa Clara County, California. The preserve is managed by the Santa Clara Valley Open Space Authority and was opened to public in 2002. The only access to the preserve had been from Alum Rock Park until 2014, when a new parking lot and trailhead opened along Sierra Road.

The Sunol Regional Wilderness is a regional park in Alameda County, the eastern San Francisco Bay Area, Northern California. It is located near the town of Sunol, south of Pleasanton and east of Fremont. The 27.74 square kilometres (6,850 acres) park was established in 1962, and is administered by the East Bay Regional Park District. The park is subject to either closure or fire restriction during the wildfire season from June through October.

Rose Peak is a peak in the Diablo Range of California and is the officially listed highest point in Alameda County, though other sources claim the high point is actually nearby Discovery Peak.

Ed R. Levin County Park is the largest park in Milpitas, California. It is run by the Santa Clara County Parks and Recreation Department and is located in the chaparral and grassland foothills of Diablo Range east of the Santa Clara Valley. Monument Peak can be accessed through trails in the park. The park's recreational facilities include a hang gliding and paragliding area, a dog park, and horseback riding areas. Ed R. Levin County Park has two lakes, Sandy Wool Lake and Spring Valley Pond. Both of them are reservoirs which collect runoff water from the hills to the east. It is home to some of the East Bay Walls. The park is named after open space advocate and Santa Clara County 3rd District Supervisor Edgar R. Levin (1908-1965).

Black Mountain, also known as Mount Day, is a mountain in the Diablo Range of eastern Santa Clara County, California, east of Poverty Ridge and Arroyo Hondo, and about 10 miles (16 km) from Milpitas. The peak is one of the highest in area. The northern half of Black Mountain is an oak woodlands while the southern half is barren. Black Mountain can be clearly seen from most parts of the Santa Clara Valley including Sunnyvale, Cupertino, Mountain View and San Jose. The peak is visible from the Mount Hamilton and Monument Peak.