Dumbarton Bridge

Dumbarton Bridge, Ravenswood Pier from Ravenswood Open Space Preserve
The Dumbarton Bridge from the Ravenswood Open Space Preserve

Trail Description and Views

South Bay Bay Trail Map

Nearby Bay Trail Segments:
Menlo Park
Don Edwards San Francisco Bay National Wildlife Refuge - Fremont
Coyote Hills
Alameda Creek Trail
Palo Alto Baylands

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Warming: This segment of the Bay Trail is not for the faint-hearted. It crosses over the Dumbarton Bridge, which can be  a thrilling, but somewhat unnerving route. Though routes over other bridges have been proposed, the only major Bay bridge passage that is officially part of the Bay Trail is the one over the Dumbarton Bridge. The Dumbarton Bridge is the southernmost bridge crossing the Bay. It runs from Ravenswood Point in Menlo Park on the Peninsula to Dumbarton Point in Fremont on the East Bay. It spans a mile-wide bottleneck in the South Bay. It's a busy bridge, with an average of over 60,000 vehicles using it daily. The Bay Trail runs over an 8-foot wide pedestrian walkway on the south side of the bridge. It is separated from the automobile lanes by a low concrete wall.

If you are traveling over the bridge for the first time, it can be a nerve-wracking experience, especially if you are nervous or acrophobic. Constant automobile traffic roars by at freeway speeds a scant few feet from the trail. If you are walking, the traffic shakes the bridge, which feels like minor earthquakes. The trail starts at Bay level, but gradually rises high above the swirling waters of the Bay. Strong Bay breezes seem to be constantly trying to push you towards the outer rail. However, the trail over the bridge is perfectly safe. It is worth taking because it provides unique and spectacular views of the Bay and Bay Area unmatched by any other segment of the trail. You might even see gray whales in the Bay from the bridge. It also provides a shortcut between the Peninsula and the East Bay.

Two fishing piers are just south of the bridge on either end. The Ravenswood Pier on the Peninsula and its counterpart on the East Bay, the Dumbarton Pier, are the remains of the original Dumbarton Bridge built in 1927 and converted to fishing piers in 1985. The old bridge was the first automobile crossing of the Bay. The center of the old bridge included a vertical lift section that was demolished and removed. The current bridge, which does not have a traffic-stopping lift span, was opened in 1984.

Just south of the bridge are the huge pipes of the Hetch Hetchy Aqueduct, carrying water from Hetch Hetchy Reservoir in Yosemite to Crystal Springs Reservoir west of San Carlos. The pipes appear from underground in Newark at the edge of a marsh,  run for miles above the surface of the marsh, end at a pump station on the Fremont bayshore, dive under the Bay, resurface in the middle of the Bay at a building at the end of a long pier, then continue on the pier to the shore at Menlo Park.

Behind the aqueduct pipes runs the Southern Pacific's Dumbarton Cutoff train bridge. The cutoff was the first bridge across the Bay. It carried freight trains from 1910 to 1982. The swing span allowed boat traffic to pass through. Now it is permanently welded open. The bridge is currently closed, and its ends are fenced off, but it may someday carry commuter rail traffic.

Near the bridge on the Peninsula are Menlo Park's Bayfront Park, East Palo Alto's Ravenswood Open Space Preserve, and Palo Alto's Baylands Nature Preserve. An accessible portion of the San Francisco Bay National Wildlife Refuge lies just north of the western bridge approach. The Ravenswood trail runs through this area.

On both sides of the eastern end of the bridge are the huge salt ponds and long levee trails belonging to the Don Edwards San Francisco Bay National Wildlife Refuge. The headquarters and visitor center for the refuge sits on a hill south of the bridge approach. North of the eastern approach to the bridge is Coyote Hills Regional Park, with its network of trails running over and around the tall hills. North of that is the Alameda Creek Regional Trail, running from the Bay to Niles Canyon. East of Coyote Hills is Ardenwood Historic Farm, a restored working farm that preserves and displays turn-of-the-century farming methods.

Access Information

The Dumbarton Bridge is part of Hwy 84. From the Peninsula, it can be reached by taking the Willow Road off-ramp from Hwy 101. Just before the bridge, an exit to the right leads to a parking lot along the side of the bridge and next to the salt ponds and marshes at Ravenswood Open Space Preserve. Steps lead from the parking lot to the pedestrian/bikeway along the bridge. The virtual tour below begins at this point.

Coming from the north, the Bay Trail is a paved multi-use path that runs along Bayfront Expressway, turns and heads up along the north side of Hwy 84, then crosses over to the south side at the University Avenue intersection. The Bay Trail from the south has gaps around Ravenswood Open Space Preserve in East Palo Alto, so it's necessary to take surface streets to reach the bridge.

To reach the bridge trail from the East Bay, take Hwy 84 west from I-880. Exit at Thornton Avenue. Turn left at Marshlands Road. Park at the visitor center parking lot for the San Francisco Bay National Wildlife Refuge headquarters. Marshlands Road from here to the bridge may be closed to vehicle traffic during the summer to protect the snowy plover, but will be open to foot and bicycle traffic. Just before the road reaches the Dumbarton Pier, a ramp leads up to the bridge.

Trail Description and Views

Click on the following pictures to see a larger version. Hit your browser's "Back" button to return. Note: the mileage readings below are from a bicycle odometer. Your mileage may vary. Trail accessibility may change. Check with the San Francisco Bay National Wildlife Refuge Visitor Center & Headquarters at (510) 792-0222. The pictures and notes here are from 1999 and earlier.

Dumbarton Bridge Walkway/Bikeway near parking lot in Menlo ParkStart at the parking lot at the southwest corner of the Dumbarton Bridge. The mileage readings begin at the stairs up to the bridge trail. The trail looks like a concrete trough along the edge of the bridge. From here, it looks like a launching ramp into the sky. A guard rail runs along top of the bayside wall. The bridge runs straight and rises steadily.

View from bridge of Ravenswood OSP shoreline and Ravenswood PierThe view improves as the trail rises. Soon it passes by the edge of the Bay at Ravenswood Open Space Preserve. Pickleweed marshes line the shoreline.

Ravenswood Pier from Dumbarton BridgeThe trail also passes by the entrance of the Ravenswood Pier (closed indefinitely since 1994).

End of Ravenswood PierThe end of the pier is reached at 0.58 miles.

 After the long climb, you finally reach the high point of the bridge at around 0.8 miles. Look over the bridge railing if you are not afraid of heights. The clearance under the bridge to the water is 85 feet, so the view from the top is liking peering over the roof of a 9-story building.

Railroad swing span bridge from top of Dumbarton BridgeDirectly to the south is the open swing span on the railroad bridge. The gap on the sides of the swing span are not that wide. It must be a challenge for novice sailors to squeeze through.

Looking north across the bridge, you can see the skylines of San Francisco and Oakland, as well as the San Mateo-Hayward and San Francisco-Oakland Bay bridges.

End of Dumbarton Pier from Dumbarton BridgeAt 0.96 miles, you cross the Alameda County line. Below the bridge, you can see the end of the Dumbarton Pier. There are likely to be fisherman at the end of this pier.

View from bridge of salt ponds on Fremont/Newark shoreOn the shore ahead, you can see the Coyote Hills to the left, the San Francisco Bay National Wildlife Refuge headquarters to the right, salt ponds in the foreground, and the Hetch Hetchy pipeline and railroad tracks to the south. Farther south, you can see the snowy white Cargill salt mounds at Newark.

Power towers with catwalks and salt ponds from Dumbarton BridgeAt 1.4 miles, you pass over the shoreline and the entrance to the Dumbarton Pier. Power lines pass overhead. You can see the power towers crossing the salt ponds, with narrow catwalks connecting them. At 1.53 miles, you pass by a levee trail on the north side of the bridge, which connects to Coyote Hills Regional Park. At 1.69 miles, you finally reach the end of the bridge trail at the junction with the bike path along Marshlands Road. Marshlands Road is now a frontage road for Hwy 84, but it used to be the approach to the Dumbarton Bridge. It runs to what's now the Dumbarton Pier. In the summer, the road is closed to automobile traffic from the refuge headquarters to the pier to protect the snowy plover. Baby plovers run around the road and are vulnerable to being struck by cars. A shuttle takes fisherman twice a day from the refuge headquarters to the pier.

End of Shoreline Trail to Coyote Hills Regional ParkTo explore the pier and bayshore, turn right and head down Marshlands Road. You start to be able to see under the bridge. A path leads under the bridge and connects to the levee trail to the north. This is the Shoreline Trail to Coyote Hills, which is a segment of the Bay Trail, and is an opportunity for further exploration. For now, continue on down Marshlands Road.

Small sandy beach on shore by Dumbarton Bridge and PierA little farther on, a small sandy beach begins and runs along the Bay to the pier.

Bell monument near foot of Dumbarton PierAt 1.99 miles, you reach the entrance to the Dumbarton Pier. A sign here explains the fishing rules. If you like, you can head down the pier and see what the fishermen are catching. Near the base of the pier are 2 round picnic tables, a pay phone, and a monument with a large bell. Turn left at the pier. To the south of the pier entrance is Gate M1. Beyond that is a wide, gravel-surfaced levee trail between the bayshore and salt ponds. This is part of the Bay Trail. Go past the gate and along the levee trail. The riprap-protected bayshore is on your right, while salt ponds are on your left. If you look carefully into the waters of the salt pond, you may see brine shrimp and brine fly larva. Swarming on the shores of the pond are harmless brine flies.

Orange-red waters of salt pond near shore south of Dumbarton BridgeContinuing along the levee, you pass by levees branching off to the left, dividing the salt ponds. None of these are accessible. The waters in these salt ponds are highly concentrated and may be red or orange in color from the salt-tolerant micro-organisms in the water.

Slough near Hetch Hetchy AqueductAt 2.72 miles, you reach the end of this Bay Trail segment. A closed levee branches off to the left. A slough passes under the trail and empties into the Bay. It runs through the marsh and heads east.

Hetch Hetchy Aqueduct pump station on bayshoreAhead is the pumping station for the Hetch Hetchy Aqueduct. Trespassing or loitering around the building or the pipes are prohibited. The huge white pipes of the aqueduct are elevated above the marsh on wooden piers. Small wooden catwalks follow along the edge of the pipe.

Train bridge trestle from east shorelineBeyond the aqueduct are the elevated rails and trestle of the old railroad line. This segment of the Bay Trail ends here. You can turn around and head back to the gate by the pier. If you continue on, there is a gravel service road that continues on and turns left to parallel the pipeline as it heads east across the marsh. The road runs for several miles between pickleweed marshes, with a slough running through the marsh on the north. However, the road deadends where Newark Slough crosses the path of the pipeline at 4.14 miles. The pipeline dives under the slough and emerges on the other shore. If you take this route, turn around and head back at the slough. At 6.25 miles, you're back at the trail gate. Go back to Marshlands Road and turn right.

Levee trail between salt ponds along Marshlands RoadAt 6.40 miles, you reach a reach a salt pond levee trail on the right. The levee is open to hiking or biking and is a side trip alternative to going straight down Marshlands Road. Go down this levee, which passes by other closed levees and pumping stations. It runs between two salt ponds. The surface is a little bumpy, and judging by the condition of the plant growth, the trail is not used much. At 7.27 miles, you reach Marshlands Road again. Turn right and continue down the road.  At 7.47 miles, you pass by the KGO radio towers. At 7.55 miles, you pass a closed levee.

Newark Slough near Refuge headquartersAt 8.00 miles, you pass a levee with a pickleweed marsh beyond. You can start to see Newark Slough.

Deadend slough east of Newark SloughAt 8.43 miles, you pass by a large bend in Newark Slough. Another slough deadends near the road here.

Marsh and slough approaching Refuge Headquarters, left of Newark SloughAt 8.51, you pass by a levee with a marsh on the right. Weeds hamper access to this levee.

Don Edwards San Francisco Bay National Wildlife Refuge Visitor CenterThe road gradually ascends the hill. At 9.28 miles, you reach the gate at the parking lot for the refuge headquarters. Turn right and head up the access road. At 9.40 miles, you reach the entrance to the visitor center. A viewing platform here provides panoramic views of the refuge and Bay. You can park your bike here. A trail leads further up the hill to provide 360 degree views of the area. The refuge and visitor center are covered in another page and offer further exploration.

Dumbarton Bridge, westbound view from walkway/bikewayTurn around and head back down Marshlands Road. By 12.16 miles, you reach the entrance to the bridge. Cross over the bridge. In this direction, you will be facing traffic, so you can see traffic approaching and will not be surprised when the cars rush past. By 13.87 miles, you reach the stairs at the end of the parking lot. If you continue on, you cross the access road to the parking lot at 14.00 miles. If you cross the road, you can reach the Bay Trail bike path heading west along the south side of Hwy 84 to University Avenue.

You can alternatively head east along the frontage road, which goes under the bridge and heads west along the north side of the bridge. Along the way, you can access the Ravenswood Trail that runs around the large salt ponds. This trail ends up back on Hwy 84 a little east of University Avenue.

Dumbarton Bridge across sloughs as seen from top of hill by refuge visitor center
View of the Dumbarton Bridge and salt ponds from the Don Edwards San Francisco Bay National Wildlife Refuge

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Developed: 12/3/99, updated 10/6/04 by Ronald Horii

Information and opinions expressed here are the responsibility of the author.