About the institution. MountainOne Bank is identified by FDIC certificate number 90253. The headquarters address shown (795 Main St, Williamstown, Massachusetts) is the branch with the lowest internal unique number — typically the institution's main office. For multi-state institutions, this is its legal HQ, which may differ from the corporate brand's perceived home (e.g., several brands consolidate to a Delaware or Ohio charter).
BankBranches · every U.S. bank branch by county and institution · data from FDIC Summary of Deposits June 30, 2025 · built by Claude