St. Georges Bay stretches roughly 20 kilometers at its mouth, bounded by Cape George on the west and Black Point on the east. The western shore runs approximately 35 kilometers from Cape George south to Antigonish Harbour. The southern shore extends another 40 kilometers from Antigonish through to the Strait of Canso. Within the bay, Port Hood Island and Henry Island break the open water. Communities with names like Ballantynes Cove, Judique, and Havre Boucher dot the shoreline, their histories intertwined with the sea.

The Strait of Canso at the bay's southern end carries considerable maritime traffic. The Canso Canal allows vessels to pass between the Gulf of St. Lawrence and the Atlantic without sailing around Cape Breton Island. The Canadian Coast Guard maintains strict vessel traffic management here, with defined sea lanes marked on nautical charts. For ships transiting the Gulf, St. Georges Bay is often the last or first open water they encounter.

The bay's shoreline belongs to two counties, Antigonish and Inverness, and their communities reflect the region's Scottish heritage. Antigonish hosts one of North America's oldest Highland Games. Fishing villages like Port Hood preserve traditions that stretch back generations. The bay itself sustains both commercial fishing and recreational boating, its waters colder than most visitors expect this far south of the Arctic.