[1] The island saw seasonal Mi'kmaq and Acadian use and was surveyed by the French Navy as a possible site for a fortified seaport prior to the selection of Louisbourg.
Important historic features on McNabs Island which are still visible include the foundations of several houses built by early settlers, an aboriginal shell midden, a cemetery containing some of the island's earliest residents, remains of a turn-of-the-century picnic ground and soda pop factory, and remnants of a once-extensive Victorian garden.
Although lighthouse officials were skeptical, the careful recording of the efficiency of kerosene by Maughers Beach keeper David George helped establish the fuel for standard use.
During World War II new gun batteries, searchlights and a steel anti-submarine net were installed between the island and York Redoubt to prevent German U-boats from entering the harbour.
The remains of Fort McNab were designated a National Historic Site of Canada in 1965 as being reflective of the significant changes in defence technology that occurred in the late 19th century.