Great Diamond Island Neighborhood Guide

Great Diamond Island sits in Casco Bay northeast of Portland's Eastern Promenade, separated from the city by a ferry ride that shapes nearly every aspect of daily life here. The island's most prominent landmark is Fort McKinley, a decommissioned Army post whose brick buildings and grounds were redeveloped into the Inn at Diamond Cove, giving the island an unusual mix of military history and quiet resort charm. Cars are essentially absent, replaced by golf carts and foot traffic, which keeps the pace unhurried in a way that feels genuinely rare this close to a small city. The seasonal rhythm is pronounced: summers draw a devoted community of residents and visitors who arrive by ferry with tote bags and kayaks, while winters shrink the population dramatically and leave the island in a kind of suspended stillness. For people willing to trade convenience for that particular quality of island life, Great Diamond offers something Portland proper simply cannot.