Two miles of paved path run from Bridge Street through Great Esker Park to Osprey Overlook Park along the Weymouth Back River. Most people who walk it, run it, or bike it treat it as a single place. It isn't. Every stretch of ground the trail crosses used to be something else: an ammunition buffer zone, a town landfill, a 19th century ironworks, a wool mill, a car dealership. The trail didn't get built on empty land. It got built on land the town had already used up once.
That history is worth knowing before you lace up, because it explains why the trail looks the way it does, why parts of it feel unfinished, and why the town is spending money on this waterway right now for reasons that have nothing to do with hiking.
What Great Esker Park Was Before It Was a Park
The esker itself, the long ridge the park is named for, formed about 12,000 years ago from sand and gravel dropped by a meltwater stream running under a retreating glacier. Trail literature for the park describes it as the highest esker in North America. Whether or not that claim holds up to a geologist's tape measure, the ridge is real and the climb is real. It's also older than everything else on this list by a wide margin.
Long before Weymouth existed as a town, the Back River shoreline held a seasonal Native American encampment and at least one trail of its own. Artifacts recovered along the river date back as far as 9,000 years, according to the Back River Trail report compiled by the North and South Rivers Watershed Association.
The land's more recent past is less scenic. The U.S. government acquired Great Esker Park in the early 20th century to serve as a geographical buffer for an ammunition depot across the river, at what is now Bare Cove Park. The park's George A. Clark Jr. Nature Center anchors the northern end of the trail today, but the site spent decades as federal land with a very different job.
Two Miles of Pavement, Five Miles of Loop
Ask two people how long the Back River Trail is and you'll get two different answers, and both will be correct.
The paved trail, the one the town and the watershed association describe as "the Back River Trail," runs about 2 miles from Bridge Street at Route 3A, through Great Esker Park and Osprey Overlook Park, ending near Wharf Street. Trailforks logs the elevation change on that stretch at 115 feet of gain and 124 feet of descent, with the route ranging from 11 to 93 feet above sea level. It's flat in places and genuinely steep in others.
The longer version, the one hikers actually log on trail apps, is closer to 5.4 miles out and back, with about 262 feet of total elevation gain and an estimated 1.5 to 2 hours to complete. That figure includes a side trail that branches off the main path near the 1.55 mile mark, crosses a salt marsh stream at a footbridge locals call the Boy Scout Bridge, and loops back along the marsh edge before rejoining the main trail. If you've only ever walked the paved 2 miles and turned around, you've done maybe a third of what's actually out there.
The Landfill, the Ironworks, and the Wool Mill
The industrial history isn't limited to Great Esker Park. Nearly every park the trail touches, or is planned to touch, was working land first.
| Site along the trail | What it used to be | What's there now |
|---|---|---|
| Great Esker Park | Federal buffer land for an ammunition depot | Nature center, trailhead, esker climb |
| Osprey Overlook Park | Town landfill | Southern trailhead, river overlook |
| Iron Hill Park | Site of the Weymouth Iron Works, built 1837 | Park land near Whitman's Pond, part of the planned southern extension |
| Undeveloped stretch north of the Weymouth MBTA station | Weymouth Wool Scouring Mill and a coal and iron ore offloading point for the Iron Works | Currently a gap in the trail network |
| Abigail Adams Park | A car dealership and a marine dredging operation | State park honoring the Weymouth-born writer and first lady |
The pattern holds across every stop: this stretch of shoreline was industrial or municipal utility land for most of the last two centuries, and the trail network is essentially a second life for ground the town had already used once and set aside.
What You'll See Depending on the Season
The trail runs alongside three waterways, the Back River, the Mill River, and Herring Run Brook. The Back River itself rises from ponds and swamps including Whitman's Pond, flows roughly 10 miles, and empties into Hingham Bay just south of Grape Island and Slate Island.
What you see from the path changes with the calendar. Spring brings the herring run, which pulls ospreys, cormorants, egrets, and striped bass back into the river, along with occasional bald eagle sightings noted by the park's naturalists. Ospreys nest in the marsh sections through the warmer months. Trail guides for the area also list wood ducks, snowy and great egrets, and blue herons as regular sightings year round.
The wildlife isn't limited to birds. Park staff have documented at least one rare diamondback terrapin found in a yard near the trail and returned it to the water with help from state wildlife officials. If you fish along the way, know before you go that some of the freshwater fisheries feeding into this system carry documented mercury and PFAS contamination, according to the watershed association's own advisory. That's not a detail most trail guides mention, but it's the kind of thing worth knowing before you keep what you catch.
Where the Trail, and the River, Are Headed Next
The town has plans to close the gaps. A boardwalk under Route 3A would extend the paved trail north to Abigail Adams State Park. A separate southern extension would run through Jackson Square to Whitman's Pond, tying Iron Hill Park and the Herring Run Park system into the same connected network. Neither project has a construction date attached yet, but both are documented as active goals in the watershed association's trail planning.
Meanwhile, a different piece of this waterway got funded first. In January 2026, the Town of Weymouth was awarded a $240,000 Seaport Economic Council grant to cover the design, permitting, and bid documents needed to dredge the Back River channel, a project expected to remove roughly 11,100 cubic yards of sediment. Mayor Michael Molisse framed it as overdue maintenance on a channel that had become harder to navigate over time, and as a step toward improving resident access to the waterfront in North Weymouth.
Two separate efforts, on the same river, in the same stretch of town. One is trying to let boats back onto the water. The other is trying to let walkers get further along it. Neither is finished, but both tell you the same thing: this waterway is getting active attention right now, not just historical plaques.
Before You Go
A few practical notes if you haven't walked it yet. There's a large parking lot on Elva Road at Great Esker Park, though the approach includes a steep hill and isn't recommended for wheelchair access. Wharf Street, at Osprey Overlook Park, and Puritan Road both offer ADA-accessible parking, with room for only one or two cars at Puritan Road. A small lot marks the trail's northern terminus at Bridge Street. Benches and trash receptacles sit at the parking areas, interpretive signage is scattered along the route with more planned, and there's a geocache stop if that's your kind of detour. Dogs are welcome but must stay leashed the entire way.
Most people who live near this trail know one piece of it well and have never walked the rest. Knowing what's actually under your feet, and what the town is planning next for the water beside it, changes how you see a path you might walk every week.
If you're thinking about what it means to live near a piece of Weymouth that's still actively changing, Condon Realty Group knows this stretch of the South Shore as well as anyone working it. Schedule your consultation.
