El Sereno Open Space Preserve

El Sereno Open Space Preserve takes its name from 2,500-foot Mount El Sereno, the ridge that forms the backdrop to Saratoga and Los Gatos. The roughly 1,600-acre preserve climbs from the foothills to the ridgeline and is mostly open chaparral, fragrant with bay laurel, chamise, coyote bush, and yerba santa, with meadows up high and a little shade along the creeks. Mule deer, coyotes, gopher snakes, and brush rabbits live in the surrounding watersheds.

Seven miles of wide, gradual trails are open to hikers, cyclists, and dog walkers, with horses on designated trails. The Montevina Ridge and Aquinas trails make an out-and-back of about eight miles along the ridge, with wide views of Lexington Reservoir, the Sierra Azul and St. Joseph's Hill preserves, and Silicon Valley; a commemorative bench for state Senator Jim Beall on the Aquinas Trail looks south over the reservoir. Purchases in 2020 and 2021 linked the 3.7-mile Aquinas Trail across the preserve, and 3.5 miles were dedicated as part of the Bay Area Ridge Trail in 2021.

El Sereno opened to leashed dogs in 2017 after neighbors asked for it; the dense brush and steep slopes keep dogs on the trail, and dogs are allowed on designated trails on a 6-foot leash, up to three per person. Parking is very limited: two spaces at the end of Montevina Road, three miles west of Highway 17, and a six-car overlook lot that needs a free permit. The preserve is one of Midpen's oldest.