islands, the steep bluffs rising from the far (east) shore, and the rolling San Joaquin Hills beyond.
Incised into the roughly 10-million-year-old marine sedimentary cliffs on the far side is a canyon that contained the largest assemblage of invertebrate fossils ever found in western North America. From sea level to their highest summits, the San Joaquin Hills exhibit eight distinct marine-terrace levels. You may recognize some of these, though massive grading for construction has greatly altered the land’s natural contours. During excavation for the Fashion Island shopping center at Newport Center (a cluster of high-rises), a great deal of petrified wood was uncovered.
Upper Newport Bay
At an easily missed fork just beyond, descend back to the wetlands, which teem with bird life. Follow the trail southward along the shoreline, crossing an inlet on a bridge, until you are forced away near a bluff-top subdivision. At the far south end of the trail, you can reach an alternative trailhead on Santiago Drive.
Loop back north along the paved Bayview Trail that parallels Irvine Avenue. This route is popular with cyclists and joggers, but hikers may prefer to veer onto the broad dirt bluff-top path between Bayview and the wetlands. Whatever route you take, you’ll eventually find yourself back at the parking area.
The north shore features a bayshore bikeway connecting Bayview Way with the west segment of University Drive. At one point, you pass over a massively timbered wood bridge spanning the marsh where it pinches against a steep, dry bluff. From that bridge, you can view three separate tiers of vegetation. The lowest is the usual low-growing, salt-tolerant group of plants like pickleweed and cordgrass. Just above the reach of the tide are plants typical of the coastal uplands, such as wild buckwheat, mulefat, and cattails. Above the level of the bridge, the bluff slope supports a dense growth of native coastal sage scrub vegetation: California sagebrush, lemonade berry, elderberry, prickly pear cactus, and cholla cactus (a coastal variant of the same cactus that grows abundantly throughout the California and Southwest deserts).
trip 2.2 Newport Back Bay Loop
Distance 10 miles (loop)
Hiking Time 4 hours
Elevation Gain 300’
Difficulty Easy
Trail Use Cyclists, dogs
Best Times All year
Agency OC Parks: UNBNP
DIRECTIONS To reach Upper Newport Bay’s Muth Interpretive Center, exit the Costa Mesa Freeway (Highway 55) at Del Mar Avenue in Costa Mesa, and go east toward the bay. In 0.5 mile, Del Mar becomes University Drive. Continue 0.4 mile to reach the interpretive center parking lot just past Irvine Avenue.
A great way to get to know Upper Newport Bay is to take the Back Bay Loop that circles the wetlands. This paved route, heavily used by cyclists and joggers, features panoramic bluff-top views, intimate marshside experiences, and diverse bird-watching opportunities. There are many places to start, but this description assumes you’re following a counterclockwise loop beginning at the interpretive center.
Like Trip 2.1, this trip begins at the parking area for the Muth Interpretive Center. It’s worth a short detour down to the center, where you can find spotting telescopes, interpretive exhibits, activities for children, and knowledgeable volunteers. When you’re ready to begin, your first goal is to reach the corner of Irvine Avenue and Santiago Drive, 1.1 miles from the start. Hikers will favor the narrow footpaths that hug the edge of the marsh (see Trip 2.1), but cyclists must take the wide paved path paralleling Irvine Avenue.
The trail ends at the intersection with Santiago Drive. Hikers can avoid busy Irvine Avenue by veering onto Santiago Drive and following it through a residential neighborhood. Where Santiago abruptly veers left and becomes Polaris Drive, continue onto a paved walking and biking path, and immediately reach a T-junction where you turn left (1.6 miles). Cyclists may prefer to follow Irvine Avenue, then turn left onto Dover Drive at Mariners Park. Near Westcliff Drive, turn left onto the paved path to rejoin the route described above.
The next 0.8-mile stretch to the Pacific Coast Highway (Highway 1) begins with a spectacular bluff-top pathway leading to Castaways Park. Pay your respects at the Marine Corps memorial, then navigate the maze of trails through the park to find the one leading southwest steeply down to Dover Drive. The Back Bay Loop leads south on the paved sidewalk to meet the PCH.
Turn left and follow the sidewalk path over the bay bridge, then make your first left onto North Bayside Drive. Just before the west entry gate at Newport Dunes Resort Marina, veer right onto another paved walking and riding path that leads behind the RV resort. When it emerges at the east entry gate, continue to Back Bay Drive, and turn left onto the road, 1.2 miles from Dover Drive.
You now follow Back Bay Drive along the east side of the bay. After passing the Back Bay Science Center in 0.3 mile, the road narrows to become one-way northbound for cars, with a wide lane on the side for self-powered travelers. This is also the terminus of the Mountains to Sea Trail (Trip 18.2). In 1 mile, reach the Big Canyon parking area with a small boardwalk. If you have time for a detour, a 0.5-mile loop on a gravel road visits a small freshwater marsh on the east side. In the early morning, bird calls almost drown out the sound of traffic, and cottontail rabbits frequent the trail.
In another 1.9 miles, make a steep ascent to a vista point on Eastbluff Drive. Turn left and follow the Back Bay Loop along Eastbluff Drive. Make your first left onto Jamboree Road, where a paved trail resumes on the west side of the road. As you approach a bridge, the San Diego Creek and Mountains to Sea Trail veer left and then crosses under the bridge, but you stay on the Bayview Trail atop the bridge. Sometimes you will see remarkable numbers of mullets jumping high out of the water at this confluence of freshwater and saltwater. Mullets do not eat flying insects, so scientists are unsure why they like to jump.
Wetlands are a rich home for aquatic life and birdlife.
Soon turn left onto Bayview Way, and find the trail again. A short spur on the right leads to streetside parking. The trail briefly splits with a paved bike path on the left and a dirt equestrian route on the right, which then rejoin before a long bridge and boardwalk. Cross the Santa Ana Delhi Channel, and reach the parking area where you began.
trip 2.3 San Joaquin Wildlife Sanctuary
Distance 2–4 miles (loop)
Hiking Time 1–2 hours
Elevation Gain Negligible
Difficulty Easy
Trail Use Good for kids
Best Times All year, open dawn–dusk
Agency
