Mount Wilson, Mountain summit in the San Gabriel Mountains, California, United States

Mount Wilson is a 5,710-foot summit of quartz diorite in the San Gabriel Mountains, a subsidiary peak of San Gabriel Peak. Its ridge carries the Mount Wilson Observatory, including the 60-inch and 100-inch telescopes and the 60-foot and 150-foot solar towers, alongside steel lattice broadcasting masts and a white observatory dome.

Benjamin Davis Wilson, grandfather of George S. Patton, built a trail along an established Tongva route in about 1852 while seeking wood for wine casks; it became the Mount Wilson Trail and later the toll road. In 1903 George Ellery Hale chose the summit for its observing conditions, and the Mount Wilson Solar Observatory was founded in 1904. A 60-inch telescope followed in 1908 and the 150-foot solar tower in 1910.

The observatory on this summit represents a place where early 20th-century astronomers made groundbreaking discoveries about galaxies and the universe. It embodies the scientific curiosity and innovation that shaped modern astronomy.

Visitors can reach the summit by car or hiking trail, with parking and basic facilities available at the top. Mountain conditions require proper footwear and caution on steep sections of the trail.

The summit's horizon over the ocean reaches 92 miles (148 km) at its 5,710-foot (1,740 m) elevation. On clear days San Nicolas Island, 107 miles (172 km) away, can be spotted, farther than Santa Catalina at 65 miles (105 km).