Calero County Park Guide

Calero County Park occupies 4,471 acres in the Santa Cruz Mountain foothills south of Almaden Valley, making it one of the largest parks in the Santa Clara County system. The park divides into two distinct zones: the reservoir area for boating and fishing, and a backcountry network with 18.9 miles of trails winding through oak woodland and ridgeline grassland. From central Almaden Valley, the drive takes about 15 minutes via Almaden Expressway to Harry Road to McKean Road. A vehicle entry fee is collected year-round at the reservoir entrance, while the backcountry Rancho San Vicente lot on McKean Road offers free parking.

Getting There and Parking

The primary entrance for backcountry hikers is the Rancho San Vicente parking area off McKean Road, where free parking is available along with equestrian staging and vault toilets. The reservoir entrance on Bailey Avenue charges a vehicle fee and provides boat launch access. Both entrances have vault toilets but no running water. The park opens at 8 AM and closes at sunset. During peak season weekends, the Rancho San Vicente lot can fill by mid-morning, so arriving early is worthwhile.

Hiking the Backcountry

The backcountry trails range from moderate loops to full-day challenges that reward experienced hikers with sweeping views of the Santa Clara Valley and Santa Cruz Mountains.

Cottle Trail to Lisa Killough Trail Loop (8.5 miles, 708 ft gain). This is the most popular route through the backcountry. The trail climbs steadily through blue oak and valley oak woodland before reaching Lisa’s Lookout, a viewpoint with panoramic views across the reservoir and surrounding hills. Plan three to four hours for the full loop. The trail earns a 4.7-star rating on AllTrails for good reason.

Bald Peaks Loop (15.8 miles). A challenging all-day route that traverses the park’s highest ridgelines with views extending across the entire south valley. Carry all water since there are no sources on the backcountry trails. Start before 7 AM in summer to beat the heat.

Stile Ranch Trail. Known for spectacular spring wildflower displays from March through May. The serpentine soils along this trail support unique plant communities including goldfields, California poppies, and several rare species adapted to the mineral-rich substrate.

Pena Trail and Figueroa Trail. Shorter options for hikers wanting a two-hour outing without committing to a full loop. These trails offer oak-shaded walking with moderate elevation change and connect to the longer routes if you decide to extend your hike.

Calero Reservoir

The 349-acre reservoir is open year-round to both power and limited-power vessels. Activities include power boating, sailing, water skiing, jet skiing, and fishing. A boat launch ramp operates from the Bailey Avenue entrance. Water levels fluctuate seasonally, and during drought years the ramp may close when levels drop too low. Check current conditions with the county parks hotline at (408) 355-2200 before planning water activities.

Fishing at Calero targets largemouth bass, carp, and crappie from both shoreline and boat. However, mercury contamination from the historic New Almaden mining district means all fish must be released. Signs posted around the reservoir warn against consuming any catch. The mercury issue affects all water bodies in the Guadalupe watershed, including nearby Almaden Lake.

Mountain Biking and Equestrian Use

Many of the backcountry trails are open to mountain bikes and horses. The Serpentine Loop provides a popular mountain biking circuit with technical sections and rewarding descents. Equestrian staging is available at the Rancho San Vicente lot with room for trailers. Riders should note that summer temperatures on exposed ridgelines regularly exceed 95 degrees, making early starts essential.

Trail Conditions and Safety

Summer heat is the biggest hazard. Temperatures on exposed ridgelines can exceed 100 degrees with minimal shade. Start early and carry more water than you think you need. Ticks are common in the grassland from October through June. Poison oak grows along many trail margins. The clay soils become extremely slippery when wet, making winter hiking after rain inadvisable on steeper sections. Rattlesnakes are present but rarely encountered on maintained trails.

Connections to Other Parks

Calero connects to the broader county parks system. Experienced hikers and riders link routes across multiple parks for 20-plus mile outings. Almaden Quicksilver County Park lies to the north, and Santa Teresa County Park is accessible via connecting ridgeline routes. The county trail system vision eventually links all three parks into a continuous open space corridor along the western rim of the Santa Clara Valley.

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