Big Island Trek

Napa County


How to Get There

From Yolo County (Winters), take Highway 128 toward Lake Berryessa.  Drive on Highway 128 to the Knoxville Berryessa Road. Turn onto Knoxville Berryessa Road and stay on the road until you get to the Oak Shores Picnic area. Drive to one of the lower parking areas, and take your boat down the hand launch boat ramp. The head out toward the island.  You can’t miss it: it’s the “big” one.

The Hike Itself

The 400-acre Big Island has no trails, and is a cross country hike.  The Island has three knolls, blue oak woodland, grassland, and some shrubs.  You can start start at the grassland on the southwestern edge of the island, hike to the northern knoll, then backtrack to the southern knoll.  The views of the lake, the Blue Ridge, Rocky Ridge, Berryessa Peak, Cedar Roughs and the rest of the shoreline are all spectacular.  The grasses are short bunch grasses on the majority of the island, but the southernmost tip of the island has some star thistle, so you might want to avoid that area.

One nice thing about the island is that very few people hike on it.  Most of the lake’s users are boating or water skiing, so there can be days when the lake is packed, but the island is empty.

On the island, you will see California Foothill Pines (Pinus sabiniana), Blue Oaks (Quercus douglasii) which are endemic to California, California Buckeye (Aesculus californica) also known as “Horse Chestnut” trees, and Manzanita (Arctostaphylos sp.)  In the spring, the fields of Lupine are outstanding.


Since there are no distinct trails on the island, the mileage varies depending on far you want to walk.


  • Fitness: easy
  • Visible Signage:
  • Parking:
  • Horses:
  • Pets:
  • Restrooms:
  • Mountain Biking:
  • Overnight Camping:

Additional Resources