Nearest town: Between Pleasanton and Livermore, CA Region: East Bay (680 Corridor) Park website: Link here Best time of year to visit: Year round (hiking is good in the cool months, and swimming/boating is good in the hot months) Features of the park: The quarry lake and the hidden trails around the arroyo (which are not visible from the road) Fees: Day use fees charged at the main entrance ($6 in 2019, EBRPD passes accepted); an alternate entrance from the back--on Clara Lane--does not charge fees.