The Cambridge Common was established by the earliest settlers of Cambridge in 1630. The northwest area of the common (now a residential zone) was reserved for milk cows. The remainder of the common was used as a training ground for the militia and a place for gathering and outdoor elections.

The famous trees on the common, now lost, are the Washington Elm, the Old Oak, and the “Whitefield tree,” where Rev. George Whitefield preached in 1740 and was critical of Harvard College's low moral standards. Under the Washington Elm, George Washington first took command of the Continental Army.