Walk into the Mountain Ave lot off Route 206 on a Saturday morning and you'll see the same thing you always see: strollers, off-leash retrievers testing the rules, a couple of trail runners cutting past the lake toward the boardwalk. The path takes you across Coventry Boardwalk, past the open fields of Coventry Farm, and eventually to the shore of the man-made lake that gives the preserve its name. It feels permanent. It feels like a park, the kind a town parks department mows and patches and budgets for every year.
Most of it isn't. For thirteen years, the people clearing downed trees and cutting back invasive vines on hundreds of acres of this system have been unpaid volunteers working without a signed agreement giving them any formal standing to do it. That changed this summer, and almost nobody outside a Monday night council meeting noticed.
Five names, one connected system
Ask a longtime resident where they walk the dog and you'll get an answer like "Mountain Lakes" or "Herrontown Woods," as if these were separate destinations you choose between. They're closer to neighborhoods within the same forest. The Billy Johnson Mountain Lakes Preserve sits at the center of a roughly 400-acre complex that also includes Mountain Lakes North, John Witherspoon Woods, the Tusculum fields, and Community Park North, laced together by more than 8 miles of interconnected trail. Herrontown Woods, across town along the Princeton Ridge, is its own 150-acre parcel with 4 miles of trail. Institute Woods and the Delaware and Raritan Canal towpath extend the network further still. Add it up and you get a fact that surprises even people who've lived here for years: more than a quarter of Princeton's land area is designated open space, according to the municipality's own accounting.
The history under your feet is not incidental scenery. The lake at Mountain Lakes was Princeton's actual ice supply for about fifty years before home freezers existed, cut and hauled by wagon by the Princeton Ice Company, which is why the site carries a listing on the State and National Registers of Historic Places. Tusculum, the meadow you cross on the boardwalk, was the country estate John Witherspoon built in 1773, and George and Martha Washington visited him there. Herrontown Woods traces to a single act of generosity in 1957, when Oswald Veblen, the first professor hired at the Institute for Advanced Study, and his wife Elizabeth donated 81 acres as Princeton's first dedicated nature preserve. Their home, the Veblen House, still stands on the property along with an 1870s farm cottage.
None of that history explains who's been keeping the trails passable. That part comes down to two small nonprofits, and until July, only one of them had anything close to formal authority.
The two names doing the actual work
Friends of Princeton Open Space has been around since 1969. It's the senior partner, credited with raising more than $5 million toward preserving over 1,000 acres and building a trail network that, in the words of its own supporters, nearly encircles the town. FOPOS runs the Mountain Lakes House, the mid-century building overlooking the lake, and leads the forest and stream restoration work at Billy Johnson Preserve itself.
Friends of Herrontown Woods is younger and scrappier. It started in 2013 as an informal group of neighbors who noticed the trails at Herrontown Woods had become impassable, blocked by fallen trees and years of invasive growth. Within a year, they had reopened more than 200 acres on their own time. They got 501(c)(3) status that same year. In 2017, they stopped a plan to demolish the Veblen House and pushed through a transfer of ownership from Mercer County to the Princeton municipality. In 2020, they signed a lease to begin restoring the house, cottage, and surrounding farmstead. All of that happened without a document that formally recognized their role in managing the land they'd spent years rescuing.
That gap is what closed this summer.
What the July vote actually changed
Earlier this summer, the Princeton Council approved two Adopt-a-Park resolutions. Steve Hiltner, who heads Friends of Herrontown Woods, told the council the agreements cover trails and habitat on 230 acres of town-owned preserved land.
"It makes official the intense and sustained work we've been doing at these preserves for the past 13 years," Hiltner said.
The resolutions formalize the partnership between the municipality and FOHW, spelling out guidelines for how the open space gets used and managed going forward. A related piece is still unfinished. A separate lease covering the Veblen House and Cottage specifically is queued for a future council meeting, and according to a memo from Open Space Manager Inga Reich, that lease can't be finalized until the New Jersey Department of Environmental Protection's Green Acres Program signs off. The trails got their paperwork. The house that anchors them is still waiting on the state.
Finding the trailheads
If you haven't explored past the lake loop, the access points are more numerous than the map suggests.
- Mountain Ave, off Route 206, has the main parking lot and restrooms for Billy Johnson Mountain Lakes Preserve.
- Cherry Hill Road has a small, easy-to-miss lot marked with a sign reading "Witherspoon Woods."
- The Unitarian Universalist Church on Cherry Hill Road offers parking with access into the Community Park North woods.
- Farm View Fields, off Route 206 near Elm Road, connects via a bike path on the Great Road to the Coventry Boardwalk.
- 600 Snowden Lane is the main lot for Herrontown Woods, next to the Botanical Art Garden, known locally as the Barden.
- 452 Herrontown Road, the Veblen House driveway, is a secondary entry point.
- Stone Hill Church, on Bunn Drive, has a trailhead behind the building.
Once you're in, the landmarks worth building a walk around are specific. In John Witherspoon Woods, look for Devil's Cave, a stack of diabase boulders formed by the same volcanic intrusion that shaped the Princeton Ridge and the Sourland Mountains. In Herrontown Woods, the trail west from the Barden leads to the Cascades, where a tributary of Harry's Brook tumbles over a bed of rocks down the ridge. Along the way you're sharing the woods with herons, kingfishers, beavers, and Eastern painted turtles, all documented residents of the lake and stream system.
On a leash, sort of
If you're bringing a dog, Princeton's own rule is more generous than what a lot of other New Jersey towns allow. Municipal code requires a leash no longer than 8 feet, in effect 24 hours a day unless the dog is confined to its owner's property. That's two feet more slack than the 6-foot cap written into several other New Jersey municipal ordinances, a small detail that matters if you've ever tried to control a dog on a shorter line through root-crossed, stream-crossed trail.
For anyone who wants their dog off leash entirely rather than negotiating eight feet of rope around other hikers, the town's dedicated Community Dog Park opened in the southwest corner of Community Park South in 2023, built out of a converted ballfield and the first permanent facility of its kind in the municipality. Quarry Park ran its own 90-day off-leash trial around the same time, and a municipal memo reported no safety incidents during the pilot, after which the council extended it as a standing privilege for the community.
Where that leaves things
Nothing about the July vote will change what you see on a Saturday walk. The same volunteers will still be out clearing the same blowdowns next spring, largely unpaid, largely unnoticed. What changed is that the arrangement is now written down, which starts to matter the moment funding, staffing, or council priorities shift in a direction that doesn't automatically favor an informal handshake. For now, the system that touches more than a quarter of this town's land still runs on the same small group of names it always has. The paperwork just finally caught up to the work.
Knowing a town this well, down to which trailhead has parking and which preserve is still waiting on state approval, is the same instinct that goes into knowing a block, a school zone, or a listing's real value before it hits the market. If you're weighing a move in Princeton or want a read on what a property here is actually worth, Jennifer Dionne brings that same level of attention to every conversation. Schedule your personalized consultation whenever you're ready to talk specifics.
