Monhegan Post Office » Island Nonprofits Return to Monhegan:Guide Lodging Shopping Arts Non-Profits Boats Food & Drink Services Go back to directory. Add to Address Book. Monhegan Post Office Monhegan Post Office Work Phone: 207-594-0609work Website: https://tools.usps.com/locations/home.htm?location=1373504 Categories: Non-Profit Updated 2 weeks ago.