Fort Loyal was a British settler refuge and colonial outpost built in 1678 at Falmouth (present-day Portland, Maine) in Casco Bay.

Fort Loyal was built in 1678 in the center of Portland at the foot of present-day India Street to protect the town from future attacks.

During King William's War, a raiding party of French and Native allies destroyed the English settlement and massacred its inhabitants in the Battle of Fort Loyal (1690).

"[3] Earthworks were constructed on the Fort Loyal site in 1775 as part of harbor defenses during the American Revolution and known as the "Lower Battery."

Today the fort's location is memorialized by a plaque on the Grand Trunk Office Building at the corner of India and Thames Streets in Portland.