In 1717, when Westborough was incorporated as the state's one hundredth town, its citizens built their first meeting house here. The hilltop became known as Powder Hill because it was the site of the town's gunpowder house, placed there for its elevation and strategic defensive location. The masonry buildings now standing, listed in the National Register of Historic Places, were erected for the Lyman School for Boys, which relocated here in 1884 and operated until 1971, when all reform schools in the state closed. A granite slab at the site came from the old school building that stood here for more than a century.