MountainOne | 1,555 followers on LinkedIn. A Genuine Commitment To Our Customers. It’s In Our Nature. | MountainOne is a mutual holding company headquartered in North Adams, MA. Banking, Insurance, and Financial Services products are offered at full service offices in the Berkshires (Pittsfield, North Adams, Williamstown) and Boston's South Shore (Quincy, Rockland, Scituate). MountainOne is dedicated to the local communities we serve, with a mission of delivering solutions of real value that help individuals, businesses, and community institutions manage their financial lives with clarity and confidence.