Positioned on the west end of Main Street in the heart of downtown Gloucester, 21 Main Street, Unit 3 offers a rare opportunity to secure a full-floor commercial presence within one of Cape Ann’s most active and walkable waterfront districts. The property occupies the entire third floor of a three-story mixed-use building and delivers a highly flexible open layout that can accommodate a wide range of commercial uses seeking character, visibility, and adaptability. The space benefits from modernized mechanical systems and a generous window line that provides both harbor and city views, reinforcing a strong sense of place and connection to Gloucester’s historic waterfront. Elevator service and full ADA accessibility ensure seamless access for employees, clients, and visitors, while two handicap-accessible restrooms further support user convenience. The building’s brick construction with steel beam reinforcement adds long-term durability and architectural integrity. A distinctive advantage of this offering is the exclusive right to a future fourth-floor expansion, presenting a compelling long-term growth opportunity subject to municipal approvals. This potential for vertical expansion is exceptionally rare in a tightly held downtown environment and enhances the asset’s strategic value for users planning for future scalability. Surrounded by restaurants, retail, and cultural destinations and located steps from St. Peter’s Square, the property sits squarely within Gloucester’s vibrant downtown district, known for its walkable streets, historic New England architecture, and active waterfront atmosphere. This location supports strong daily foot traffic, lifestyle amenities, and a compelling environment for businesses seeking both functionality and a unique coastal identity.