Petersham State Forest is a 1,742-acre forest located in the town of Petersham in Massachusetts. Visitors can enjoy hiking, fishing, camping, and picnicking in the area. The forest is known for its scenic vistas, old-growth trees, and diverse wildlife including black bears, bobcats, and coyotes.

There are several points of interest within the forest, including the Swift River, which runs through the forest and offers excellent fishing opportunities, and the Tully Lake Recreation Area, which is a popular spot for camping and boating. The forest also features two historic fire towers that offer stunning views of the surrounding landscape.

Interesting facts about the area include its designation as a National Natural Landmark due to its old-growth forest and unique geological features. The forest is also home to several rare plant species, including the Eastern Hemlock and Mountain Laurel.

The best time of year to visit Petersham State Forest is in the fall when the leaves change color and the weather is mild. However, the forest is open year-round and offers different experiences depending on the season. Spring brings wildflowers and blooming trees, while winter offers opportunities for snowshoeing and cross-country skiing.