The Amoskeag Manufacturing Company's granite quarry was opened in 1873 on Oak Hill, then called Company Hill. For 10 years granite was pulled from the quarry and used in construction around the city, until an underground spring was broken into, filling the massive hole with water to a depth of 60 feet. In the 1920s, the quarry, from then on known as Amoskeag Ledge, became a popular swimming and diving destination in the city. The Ledge is known to have claimed at least 10 lives, including that of Hector Boisvert, who drowned there in 1929. His body has never been found.

In the 1930s efforts were begun by the Amoskeag Company and the City of Manchester  to keep the public out. They filled a good amount of it with soil from another part of the city, but there is still a considerable drop on one side of the quarry to this day, as you'll see in the pictures below.