[4] The forest came into state ownership via the estate of William C. Whitney, President Grover Cleveland's Secretary of the Navy.

The purchase of the initial 11,000 acres (4,500 ha) was made in 1915 for a total of $60,000, part of which came through the pledge of a group of Berkshire residents.

[3] The name "October Mountain" is said to have been bestowed by author Herman Melville, whose home in Pittsfield overlooked the area.

The eponymous October Mountain is a ridge that rises steeply above the Housatonic River valley to the west and contains the forest's highest point.

The central portion of the forest is an uplands area that includes several reservoirs, and the Washington Mountain Marsh.