Before 1971, Plainsboro was — in its own residents' words — "a sleepy farming community" of about 1,200 people and 1,500 cows. As development pressure swept New Jersey in the early 1970s, township leaders made a deliberate choice: build a master plan around open space preservation rather than let farmland disappear the way it had elsewhere in the state.

That choice compounded over five decades. Today, roughly half of Plainsboro's land area is permanently preserved — including the roughly thousand-acre Plainsboro Preserve and Bunker Hill/Bulk Farm, home to river otters, beaver, bear, deer, fox, and coyote inside one of the most densely developed states in the country.

The preservation effort wasn't just planning-department policy — for families who farmed the land for generations, it's described as heritage. One longtime resident traces his family's connection back to a great-grandfather who left northeastern Pennsylvania at the turn of the century to farm in Plainsboro; the master plan's open-space commitment is what kept those fields from becoming just another subdivision.

The preserved land isn't fenced off — it's used daily for kayaking, birdwatching, hiking, and active recreation, and access to the Preserve itself is free. Township officials point to the master plan as the actual mechanism: it's what gives the Planning Board the guidance to weigh development against preservation on every application that comes before it (see the Development tracker for what that looks like in practice today).

Built from a primary-source township video, archived June 29, 2026. This page covers open-space history specifically, not a full municipal history — we'll expand it as we verify more.