The Otter River State Forest is a state park and recreation area in Baldwinville, Massachusetts. It is noted for being the first property that the State Forest Commission has acquired.

Founded in 1915, the Otter River State Forest served largely as small farmlands in the nineteenth century. When it was acquired by the state in the early 1900s, it was reforested. It was planted with groves and pines and even the Civilian Conservation Corps helped grow the forest and develop the park.

Featuring the Beaman Pond, the Otter River State Forest is ideal for camping, fishing, hiking, mountain biking, picnicking, swimming, cross country skiing, snowmobiling, and even hunting under a couple of restrictions. Yurt camping is also available at the park.