Overview
Rancho San Antonio Open Space Preserve sits at the boundary of Los Altos Hills and Cupertino in Santa Clara County, roughly 10 miles southwest of downtown San Jose. Managed by the Midpeninsula Regional Open Space District (MROSD), the preserve covers more than 4,000 acres of oak woodland, chaparral, riparian corridor, and grassland climbing toward the Santa Cruz Mountains.
The preserve is one of the most-visited open spaces in the Bay Area, largely because a working farm — Deer Hollow Farm — sits within its boundaries and is operated by the City of Mountain View as an environmental education center. Visitors come for the combination of accessible flat trails near the parking area and more challenging ridge routes that reward hikers with panoramic views over the South Bay.
Wildlife is diverse: deer, coyote, wild turkeys, and a variety of raptors are commonly spotted. The preserve connects to Monte Bello Open Space Preserve, allowing experienced hikers to string together routes covering significant elevation gain and varied terrain in a single outing.
Before You Go
No admission fee is charged to enter the preserve, though parking fees may apply at the Rancho San Antonio County Park lot adjacent to the trailhead — verify current rates and payment methods with Santa Clara County Parks or MROSD before visiting, as these can change.
Permits and reservations: During peak periods (weekends and holidays), the parking lot fills quickly and a timed-entry or parking reservation system has been used in the past. Check the MROSD website (openspace.org) ahead of your visit to confirm whether advance reservations are required, as policies have evolved since COVID-era changes.
What to bring:
- Adequate water — there are no reliable potable water sources on the upper trails
- Sunscreen and a hat; ridge trails have minimal shade
- Layers — morning fog and afternoon wind can shift temperatures significantly
- Trail map (downloadable from MROSD's site) or a GPS app loaded offline
Dogs are not permitted on any trails within the MROSD portion of the preserve. Leashed dogs are allowed in the adjacent Santa Clara County Park section near the parking area — verify boundaries on the official trail map.
Getting There
By Car
The main trailhead and parking lot is located at the end of Cristo Rey Drive in Los Altos Hills. From US-101, take the Foothill Expressway exit and head southwest; signage for Rancho San Antonio County Park is posted along the route. The parking lot is shared between Santa Clara County Park and the open space preserve.
By Public Transit
Santa Clara Valley Transportation Authority (VTA) bus routes serve the general corridor, with the closest stops typically requiring a walk of half a mile or more to the trailhead. Verify current routes, stop locations, and schedules at 511.org or the VTA website, as service levels change periodically. Caltrain's San Antonio station in Mountain View is within cycling distance for confident riders.
By Bicycle
A paved, multi-use path connects the Permanente Creek Trail system and nearby neighborhoods to the preserve entrance — a practical option for visitors based in Mountain View, Sunnyvale, or Los Altos.
Getting Around
All travel within the preserve is on foot or by bicycle (on designated multi-use trails). The trail network is well-signed with wooden posts at most intersections; distances and destinations are marked. Trails range from flat, wide farm roads near Deer Hollow Farm — suitable for families with young children or strollers — to steep, narrow singletrack climbing toward Rogue Valley and PG&E Road.
Pickup a paper trail map at the trailhead kiosk or download the MROSD map in advance. Cell coverage can be unreliable on upper ridge trails, so offline maps are advisable. The Rancho San Antonio trail system connects directly to Monte Bello Open Space Preserve via trails such as Rogue Valley and Wildcat Loop, opening up significantly longer routes for prepared hikers.
Things to See & Do
Hiking
The preserve offers roughly 24 miles of trails. Popular routes include:
- Deer Hollow Farm Loop (approx. 3 miles, easy): Flat farm roads past the working farm and along Permanente Creek — ideal for families.
- Wildcat Loop (approx. 5–6 miles, moderate): Climbs through oak and chaparral with open grassland views; combines several named trails.
- PG&E Road to Monte Bello connector (strenuous, significant elevation gain): Suitable for experienced hikers seeking a half-day challenge with ridge views.
Deer Hollow Farm
This living-history farm, operated by the City of Mountain View, maintains heritage-breed livestock and gardens. It functions primarily as an educational facility for school groups, but the public can walk through the farm area during open hours. Verify current public visiting hours directly with the City of Mountain View Parks and Recreation Department, as schedules vary seasonally.
Wildlife Watching
Dawn and dusk are the best times to spot deer, coyotes, and raptors including red-tailed hawks and American kestrels. The riparian corridor along Permanente Creek is particularly productive for birdwatching year-round.
Running
The preserve is popular with trail runners given its varied terrain and well-maintained surfaces. The flat lower trails are frequently used for training runs; the upper routes provide interval-friendly climbs.
Food & Drink
There are no food or beverage vendors inside the preserve. Bring everything you need, including sufficient water — the upper trails have no reliable water access.
The nearest dining options are in Los Altos along Foothill Expressway and El Monte Avenue, and in Mountain View's downtown Castro Street area, roughly 10–15 minutes by car. A modest selection of grocery stores and cafes in Los Altos can supply picnic provisions before your visit.
There is a picnic area near the Deer Hollow Farm trailhead corridor — a practical spot for a packed lunch after a morning hike.
Practical Information
Hours: The preserve is generally open from dawn to dusk (30 minutes before sunrise to 30 minutes after sunset), but verify current hours on the MROSD website as seasonal adjustments apply.
Restrooms: Portable restrooms and/or vault toilets are available at the main trailhead parking area. Facilities on upper trails are limited or absent.
Fees: Verify current parking fees with Santa Clara County Parks before visiting. Entry to the open space trails themselves has historically been free.
Emergency contacts: In an emergency, call 911. The MROSD rangers patrol the preserve; a ranger station is located near the Deer Hollow Farm area. Cell service can be poor on ridge trails — inform someone of your planned route before heading out.
Leave No Trace: Pack out all waste. Fires and smoking are prohibited throughout the preserve. Stay on marked trails to protect sensitive grassland and chaparral habitat.
Safety
Wildlife: Mountain lions are present in the Santa Cruz Mountains and have been recorded in and around the preserve. MROSD posts guidance at trailhead kiosks — read it before entering. Rattlesnakes are active in warmer months; watch where you step and place your hands.
Heat: Summer afternoons can be hot on exposed ridge trails. Start hikes early, carry at least two liters of water per person, and turn back if conditions become uncomfortable.
Trail conditions: Trails can be muddy and slippery after winter rains. MROSD occasionally closes specific trails after significant rainfall to prevent erosion damage — check trail status on their website before visiting during or after wet weather.
Navigation: Intersections are signed but some junctions are close together. Confirm your route on the official map before setting out, particularly if planning a longer loop connecting to Monte Bello.
