Mount Hamilton is a mountain in the Diablo Range in Santa Clara County, California.

[7][8][9] On August 26, 1861, while working for Josiah D. Whitney on the first California Geological Survey, William H. Brewer invited local San Jose preacher (and Brewer's personal friend) Laurentine Hamilton to join his company on a trek to a nearby summit.

Nearing completion of their journey, Hamilton, in good humor, bounded for the summit ahead of the rest of the men and claimed his stake.

It has provided a glimpse of the extreme weather conditions that occur on the Diablo Range, especially in the winter months.

Due to frequent thermal inversions during the summer, it is often warmer on Mount Hamilton than in San Jose.

[15][16] Copernicus Peak is located 0.8 miles (1.3 km) to the northeast from Mount Hamilton, and is the highest point in Santa Clara County.

Built in 1875–76 in anticipation of the observatory, and the need to carry materials and equipment up the mountain in horse-drawn wagons, the grade seldom exceeds 6.5 percent.

The road rises over 4,000 feet (1,200 m) in three long climbs from San Jose to the mountain top.

[18] Thanksgiving consistently draws hundreds of cyclists and is frequently the final climb in the annual Low-Key Hillclimb Series[19] which attracts some of the region's best climbers.

The upward trek is interrupted by two descents, first into Grant Ranch County Park, and again to cross Smith Creek.

Quimby Road offers a shorter way from San Jose to Grant Ranch, but is considerably steeper.

The main observatory building offers free 15-minute guided tours of the Great Lick refracting telescope.

[20] The Babb Creek drainage comprises some of the watershed draining the slopes of Mount Hamilton.

[21] In 1978, California Department of Fish and Game warden Henry Coletto urged the department to choose the Mount Hamilton area as one of California's relocation sites under a new statewide effort to restore tule elk (Cervus canadensis ssp.