Near the turn of the century, Pole Hill was called "the Grove", and was a recreational area sporting a picnic area and a dance hall. Sitting on the bend of the Shawsheen River in Ballardvale, it was a busy spot for out-of-town visitors coming up the railroad from Boston. The dance hall was permanently shut down after a gun duel between two men at a large picnic event ended with one man dead.
These days the conservation land is a much milder scene, though it still has a picnic area. You can even hike up to the old site of the dance hall at the top of the hill. One hike through the trails will make it evident why the area was such a popular hangout.