A significant number of seasonal residents causes the population to swell to over 700 during the summer.

[citation needed] He died in 1765, and willed the island to his nine surviving children.

Soon after, other settlers arrived to make a livelihood out of farming, fishing, and catching lobsters.

[citation needed] During World War II, Casco Bay became United States Navy base Sail for destroyers escorting HX, SC, and ON convoys of the Battle of the Atlantic.

[6] Facilities constructed on the island included the Torpedo Control Officers School of the Portland Naval Training Center, a navy supply pier with a naval fuel annex[7] often cited as a source of contamination for both the island's marsh and Casco Bay, and the Naval Auxiliary Air Facility Casco Bay seaplane base operated as part of Naval Air Station Brunswick from 14 May 1943 to 15 December 1946.

[8][9] The United States Army Coast Artillery Corps built two batteries of 90 mm dual-purpose guns on the island as the Long Island Military Reservation, part of the Harbor Defenses of Portland.

[10] After the war, tourism became the most popular industry, and several small stores, a fire station, and a K–5 school (1953) were built.

[citation needed] The island was originally part of the city of Portland, which re-evaluated property taxes in 1990.

Many residents felt this move created an unfair discrepancy between the money paid to the City of Portland and the services they received in return.

These archives also include copies of the local and national news coverage given to the community during its "rebellion".