Flag Hill Loop, Sunol CA


• 5-star hikes
• 4 to 5 mile options
• Moderate | Gain 980 to 1,060 feet
• Sunol, CA | San Francisco Region
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A high-altitude vantage point overlooking a lush, forested landscape. In the foreground, two hikers sit on large rocks, facing away from the camera. They wear wide-brimmed hats and backpacks, suggesting they have trekked to this scenic spot. Below them, rolling green hills stretch into the distance, dense with trees and vegetation. A winding road snakes through the lower terrain, leading toward a shimmering body of water further back. The sky is clear and bright blue, enhancing the serene, open feel of the scene.
Looking towards Calaveras Reservoir from Flag Hill.

Vast rolling meadows, rocky scrambles, and creekside paths await on this diverse loop through California's rolling grasslands and oak woodlands. Better yet less popular than the hike to Alameda Canyon, the Flag Hill Loop offers a quieter, more scenic alternative, showcasing Sunol Wilderness Regional Preserve's varied terrain and expansive views. The route begins with a gradual ascent to the summit of Flag Hill (1,360 feet), climbing through oak woodlands speckled with mistletoe-laden trees, where goldfinches and woodpeckers flit among the sparse shade

After enjoying the summit’s sweeping views, pastoral scenes unfold along Flag Hill Road toward High Valley Camp, where cattle graze in lush grasslands. We've presented you with two options - a shorter loop that leads down the wide Hayfield Road or a longer route continuing onto Indian Joe Trail for a more varied experience.
⬤ 5★ Flag Hill & Indian Joe Loop   4.5 mi loop, moderate, gain 1,060 ft
GPX File · AllTrails · Directions GPX?
⬤ 4★ Flag Hill & Hayfield Rd Loop   3.6 mi loop, moderate, gain 980 ft
GPX File · AllTrails · Directions
 $  East Bay Parks fee

Indian Joe Trail follows Indian Joe Creek, winding along a narrow path that offers intermittent shade as it descends back toward the trailhead. The trail is moderately steep and mostly shaded, providing welcome relief from exposed sections of grassland. While keeping an eye out for snakes, take a moment to explore Indian Joe Cave Rocks—an intriguing cluster of boulders perfect for scrambling.

Spring offers the best hiking conditions, with verdant hills and mild temperatures, though the trail remains accessible year-round with proper preparation. Summer temperatures can reach the mid-90s, making sun protection and adequate hydration essential. The terrain features a blend of open grasslands and wooded creek corridors, creating distinct microclimates throughout the loop.

A lone hiker dressed in a blue shirt, gray pants, and a backpack strides along a narrow dirt trail through a verdant forest. The path winds gently, flanked by towering trees with thick trunks and dense foliage. Tall grass and undergrowth frame the scene, lending depth to the natural landscape. In the background, rolling greenery blankets a distant hill beneath a crisp, cloudless blue sky.
Hiking up Flag Hill Trail, with the summit in the background.

A person wearing a yellow shirt and a white hat crouches on a grassy hilltop dotted with wildflowers in shades of purple and yellow. They appear to be taking a photo or closely examining something in the grass. The rolling landscape extends into the distance, with scattered trees and communication towers atop nearby hills. The bright blue sky enhances the vibrant scene, conveying a peaceful, immersive connection with nature.
The cool spring weather is a great time for wildflowers.

A tranquil rural landscape featuring rolling green hills, scattered trees, and a clear blue sky. In the foreground, a grassy field hosts a few cows grazing. A red barn sits in the middle distance, enclosed by a wooden fence. Winding paths weave through the hills, which are dotted with clusters of trees and shrubs. The scene evokes a peaceful, pastoral charm.
Lush pastoral scene of Sunol Wilderness.

A hiker dressed in a blue shirt, gray pants, and a black cap walks along a narrow dirt trail in a grassy clearing. They carry a black backpack and head toward a dense wooded area. To the right of the trail, a dry creek bed is scattered with rocks and fallen branches. The surrounding trees cast dappled shadows on the path, and the sky overhead is clear and blue, suggesting a bright, sunny day. The scene exudes a sense of tranquility and adventure.
Returning on the narrow and partly shaded Indian Joe trail.

Tangents:
• Official: East Bay Parks
• AllTrails Public: Flag Hill & Indian Joe, Flag Hill & Hayfield Rd
• Facebook Group: Comment, Follow Us


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