Flag Hill

Flag Hill
Sunol Regional Wilderness, SunolA moderately strenuous hike will take you to the top of Flag Hill, which is composed of layers of fossil-rich sandstone formed some 13 million years ago. You’ll enjoy great views and good opportunities to watch birds and other wildlife. Ambitious hikers may take an optional detour to Indian Joe Cave Rocks.

EastBay Parks: Sunol Regional Wilderness, Sunol, CA

Hike Statistics

Distance: 3.5 miles round trip
Time: Allow 3 to 4 hours
Grade: Starts with a steep up-grade and ends with a moderate down-grade.
Suggested Age: Webelos

Hike Description

Begin this hike by crossing Alameda Creek on the footbridge near park headquarters. Turn left (downstream). After a short distance, Flag Hill Trial will take off uphill, to the right. The trail zigzags up the face of the hill (make sure your hikers understand why it’s important not to shortcut switchbacks). After about a mile of rather steep uphill hiking, you’ll reach the top where you’ll probably want to take a good snack or lunch break. While on top, watch for red-tailed hawks (the red upper surface of the tail is visible when the hawk turns), turkey vultures (which hold their wings in a slight “V” and teeter in flight), and maybe even a golden eagle or falcon.

Continue your hike by dropping down the back side of Flag Hill, turning right when you reach High Valley Road. High Valley is a reservable hike-in campsite suitable for Boy Scout troops. Return to the cars by way of Hayfield Road.

Alternate Routes

For a more ambitious hike with a highlight the boys are sure to love, take a detour to the Indian Joe Cave Rocks just after you go through High Valley. Remind the boys about rattlesnakes before letting them explore these huge jumbled boulders. Return to the cars by way of the Indian Joe Creek Trail. The detour will add about 0.7 miles to your total distance, and is well worth it.

This hike is also nice in reverse (visiting the Cave Rocks first, then Flag Hill), but going down the steep Flag Hill Trail can be hard on the knees.

Historical and Natural Features

Sunol Regional Park area was inhabited by the Ohlone Indians for about 4000 years. In 1797, when the mission was built at Mission San Jose, most of the Indians moved to the mission. The Indian camp was located on the same site as the Green Barn and park office are now located.

In 1865, a family named Geary homesteaded the area and built what is now the access road into the park, Geary Road. Enough people moved into the area to establish a school.

The Sunol Valley has offered recreational opportunities for several generations to campers. Campers from San Francisco set up campsites in the Sunol Valley before the turn of the century. The Gearys took part in encouraging recreational use of the area by selling goods and providing transportation to the campsites from the railroad station in Sunol.

On the Fourth of July in 1903, a group of children climbed a hill located north of the present park headquarters, and planted a flag. The hill thereafter was known as Flag Hill.

In the 1930’s the land was purchased by a man named Brinker. He built the barn at High valley, and perished while fighting a fire on the property.

The East Bay Regional Park District purchased the land in 1959. Sunol Regional Park opened to visitors in 1960.

Administration

East Bay Regional Park District
2950 Peralta Oaks Ct.
PO Box 5381
Oakland, CA 94605-5369
(510)635-0135 (General Info)
(510)636-1684 (Group Camping reservations)

(510)862-2244 (Sunol Regional Wilderness Headquarters)
Call this number to reserve the “School Camp” for your group.

Suggested Season:

Late spring to late fall.

Location/Directions

Sunol Regional Wilderness
Southeast end of Geary Road
Sunol, CA 94586

From the Fremont area, drive north on I-680 and exit at Calaveras Road.Turn right on Calaveras and proceed to Geary Road, which leads directly into the park.

From the Oakland / Berkeley area, drive east on I-580 to the junction with I-680 in Pleasanton. At the junction, go south on I-680 and exit at Calaveras Road/Highway 84 just south of the town of Sunol. Turn left onto Calaveras Road and proceed to Geary Road, which leads directly into the park.

From the Walnut Creek / Danville area, go south on I-680 and exit at Calaveras Road/Highway 84 just south of the town of Sunol. Turn left onto Calaveras Road and proceed to Geary Road, which leads directly into the park.

Park Facilities

  • Visitor Center
  • Picnic Areas (tables, grills, water, restrooms)
  • Reservable Group Campsites
  • Reservable Family Campsites
  • Horses for hire
  • Hiking and Bicycling trails

Limitations and Cautions

  • Remember money for parking
  • Poison Oak is abundant
  • Rattlesnakes share the park with visitors
  • Exercise caution when hiking downhill on steep grades
  • Sunol Regional Park shares the area with the San Francisco Water District and private land owners. Please respect the “NO TRESPASSING” signs.

Activity Suggestions and Other Comments

Sunol Regional Park offers an excellent naturalist program. Make reservations and allow time for the Scouts to explore the flora, fauna, and natural environment. After the hike your group might enjoy a barbecue at one of the picnic sites.

Advancement Opportunities

Webelos:
Forester, Geologist (Sunol has some great rock formations), and Naturalist