Gallows Hill was once the name for the northern portion of Cambridge Common, the public park near Harvard Square that has been common land since 1630. The north end of the park has a large playground, and the grounds are maintained by the Cambridge Department of Public Works. This is a place shaped over centuries: established in 1630 as a common area to serve as grazing pasture for ox, sheep, and cows and as a woodlot, it was also used as a military training ground.
At its greatest extent it stretched from what is now Linnaean Street in the north all the way south to Harvard Square between Massachusetts Avenue and Garden Street, an area comprising roughly 85 acres. The northern portion was once known as Gallows Hill, located today west of Massachusetts Avenue around Lancaster Street, where public executions took place. On September 22, 1755, two enslaved African Americans, Mark and Phillis, were executed after being accused and convicted of poisoning their enslaver, John Codman of Charlestown; Phillis was burned at the stake and Mark was killed by hanging on gallows some ten yards away from the stake.
Notice the playground to the north and the wide sweep of green stretching south toward Harvard Square.