Don Edwards San Francisco Bay National Wildlife Refuge,
U.S. Fish and Wildlife Service,
Alameda County
In brief:
5.9 mile loop skirting salt ponds south of the Dumbarton Bridge.

Distance, category, and difficulty:
This 5.9 mile loop hike, like all hikes here, is very easy. Trail elevation ranges from sea level to about 135 feet. Total elevation change for this hike is about 170 feet.

Completely exposed.

Trail traffic

Trail surfaces
Dirt trails and fire roads.

Hiking time
2 1/2 hours.

Any time is nice.

Getting there:
From CA 84 in Alameda County, exit Paseo Padre Parkway/Thornton Avenue (this is exit 36, the first exit after the toll plaza, traveling east). Drive south on Thornton about 0.8 mile, then turn right into the refuge. Continue about 0.5 mile, and turn left into the parking lot at the end of the road.

Get driving or public transit directions from Transit and Trails:

GPS Coordinates* for Trailhead:
Latitude 3731'55.39"N
122 4'22.99"W
(* based on Google Earth data, shown as degrees, minutes, seconds)

Gas, food, and lodging:
There are no services in the immediate area: gas, stores, and restaurants in Newark. No camping.

Trailhead details:
No parking or entrance fees. Lots of parking in a paved lot. There are designated handicapped parking spots, and wheelchairs should be able to travel short distances in the refuge. The park is open from 7 a.m. to dusk. Drinking water, maps, and restrooms available at the Visitor Center (now located on Marshlands Road before you get to the main parking lot). Pay phone at edge of parking lot. This park is accessible by public transit. Visit for details.

Trails are open to hikers and cyclists. Dogs are permitted on leash only, only on Tidelands Trail.

The Official Story:
Department of Fish and Game's Don Edwards page
Refuge brochure (pdf)
Park office 510-792-0222.
Cargill Salt's website

Map Choices:
• Use AAA's San Francisco Bay Region map to get there.
Refuge map (pdf)
South Bay Trails, by Jean Rusmore, Betsy Crowder, and Frances Spangle (order this book from has a simple map and a suggested hike.
• East Bay Trails, by David Weintraub (order this book from has a good map and a featured hike.

Don Edwards Wildlife Refuge in a nutshell -- a printable, text-only guide to the featured hike.

View photos from this hike.

Go to Bay Area Hiker Home page

Don Edwards San Francisco Bay National Wildlife Refuge, with over 23,000 acres, proclaims itself the largest urban wildlife refuge in the country. Trailhead Most of the refuge stretches along the marshy shoreline north and south of the Dumbarton Bridge, but Bair Island, in San Mateo County, is also part of the system. The refuge's headquarters are located at the edge of industrial Newark, and some of its wetlands are salt ponds managed by Cargill Salt. From the Visitor Center two trails depart: one a short and easy self-guided loop, and the other a 5 mile flat circuit around the salt ponds. The two can easily be strung together for a 6+ mile tour, perfect for a daily run or easy walk.
     Start at the edge of the parking lot and begin walking up the paved trail. After a few steps a gravel path veers off to the right. Turn right. The path soon ends at a paved road and signed junction. Cross the road and go straight. BoardwalkAfter about 350 feet you'll reach a signed junction just before an interpretive display. Turn right, toward Tidelands Trail and Pavilion. The gravel path descends a bit, then turns sharply left (a path to the Learning Center breaks off to the right). A tangle of blackberry vines sprawls on the right and fennel is common all around. The trail transitions to an elevated boardwalk above a sea of pickleweed. When the boardwalk passes over Newark Slough, look in the water for snowy and great egrets. A little red building on the right serves as a picnic shelter. At 0.25 mile, the boardwalk ends at a signed T junction. Turn right.
      Newark Slough Loop Trail begins a long circuit around a series of salt ponds. Depending on the season and the stage of salt development, the water may range from green to mauve. Newark Slough Loop TrailWhen I visited in late June these ponds echoed the colors of a sunset; violet in the deepest water and burnt orange at the shoreline, with a thick crust of salt encircling them like a rimmed margarita glass. Avocets, stilts, terns, and swallows were all common on my early summer hike, and according to the refuge's bird checklist, a variety of other birds can be spotted, from the endangered clapper rail to white pelicans to kites, hawks, ospreys, and eagles. Trailside vegetation is sparse, and consists mostly of salt-loving ground cover like pickleweed and alkali heath, which boasts tiny purple flowers in summer. The initial miles of Newark Slough Trail run between the slough and salt ponds, with nice views north to Coyote Hills, and west to the Santa Cruz Mountains. View west across the salt pondUnfortunately traffic noise from CA 84 is noisy and constant, although as the trail bends south you'll enter a quieter area of the refuge. The trail remains perfectly flat. When I visited the southernmost shoreline was the saltiest, and even the trail surface was coated in places with a thick layer of crystals that crunched underfoot. Walking east you'll have good views of Mission Peak and Walpert Ridge, home to Garin/Dry Creek Pioneer Park. Near some Cargill Salt buildings the trail passes around a gate and takes a sharp turn left. On the right a depressingly barren field buffers noise from Thornton Avenue. At 4.32 miles Newark Slough Loop Trail heads left, while a dirt road veers right. You'll pass around another gate and return to a more peaceful area, once more traveling between Newark Slough and the salt ponds. At 5.04 miles you'll reach a signed junction near a picnic table. Turn right onto Tidelands Trail.Tidelands Trail
     A bridge passes over Newark Slough, then return to solid ground. Ignore a few shortcut trails and follow Tidelands Trail to the left as it climbs easily through grassland dotted with buckwheat, California poppy, horehound, and mustard.At 5.17 miles you'll reach an interpretive display and a junction. Stay to the right on Tidelands Trail.
The trail ascends slightly, passes a closed trail on the left, then curves left and drops through an area with nonnative vegetation including century plant. Squirrels are common in this part of the refuge. At 5.37 miles a spur trail heads right from a signed junction. Stay to the left on Tidelands Trail. As the broad trail ascends, you might notice toyon mixed through the grassland, along with coyote brush and a few acacia trees. At 5.44 miles Harrier Trail slips off to the right. Continue straight on Tidelands Trail. Persisting uphill at an easy grade, the trail features interpretive displays every so often. In summer look for butterflies feeding on buckwheat plants. Hilltop overlookAt 5.62 miles trails depart to the left and right, but continue straight a few steps further, to the hilltop. Take a short flight of steps uphill on the left, where at about 5.68 miles you'll reach a lookout and the refuge's highest elevation. When you're ready go back down the stairs, then turn left.
     Tidelands Trail descends, with sagebrush common along the trail. At 5.74 miles stay to the right as another trail feeds in from the left. The trail shifts from dirt to pavement just before the Refuge Headquarters (the old visitor center). Follow the pavement back downhill to a junction at 5.90 miles. Turn right and retrace your steps back to the trailhead.

Total distance: 5.93 miles
Last hiked: Friday, June 28, 2002