Lick Observatory is located on the summit of Mt. Hamilton in the Diablo Range east of San Jose.
From Interstates 101, 280, 680: take Alum Rock Avenue exit from Interstate 680 north. Turn right onto Alum Rock Avenue. Take another right on Mt. Hamilton Road (California Route 130). Allow at about one hour from San Jose, and please drive carefully as the road is good, but winding. There is bridge construction on the way at Smith Creek.
From the east: take Interstate 580 west to Interstate 680 south. Then follow the directions above. Alternatively, you may take take California Route 130 to Mt. Hamilton from the east, but please allow about 1-3/4 hours from Interstate 5 to reach the Observatory. The road is long and winding, but well-maintained. Take the Patterson exit off Interstate 5, and go west on Puerto del Canyon Road (away from Patterson.) At the Junction Cafe, turn left to stay on California Route 130.