The west side and summits of Berry Mountain are located within Hancock, Massachusetts; the east slopes are located within Pittsfield. The ridgeline continues south from Berry Mountain as Pine Mountain and Tower Mountain; it continues north as Berry Hill. Berry Mountain is bordered by West Hill to the west across the Wyomanock Creek valley. The west side of the mountain drains into Berry Pond Creek, then Wyomanock Creek, thence into Kinderhook Creek, the Hudson River and Long Island Sound. The east side drains into Lulu Creek and Parker Brook, thence into Onota Lake, the Housatonic River, and Long Island Sound.