Fort Cowan Cowan, Military fortification in Moreton Island, Australia

Fort Cowan Cowan is a military fortification on Moreton Island featuring two 6-inch naval guns, concrete pathways, four ammunition magazine huts, and foundations of support buildings scattered across the site. The layout reveals how a coastal defense battery was organized during the middle of the 20th century.

The fort was built in 1937 and operated until 1945 as part of Brisbane's coastal defense system, monitoring shipping and protecting against potential Japanese naval attacks. Its presence reflects Australia's concerns about maritime security during World War II.

The fort's name comes from the Cowan Cowan township on Moreton Island's western shore, where the battery stood within an Australian Army perimeter that also housed a Royal Australian Navy establishment, RAN 3 Cowan Cowan. The site is also known as Fort Cowan and Cowan Cowan Battery, and it joined the Queensland Heritage Register on 1 October 2007.

Reaching the site requires taking a boat to Moreton Island, as it is only accessible by water. The pathways and structures can be uneven depending on weather conditions, so sturdy footwear helps with navigation.

Fort Cowan Cowan is also known as RAN 3 Cowan Cowan: within the Australian Army perimeter, the Royal Australian Navy ran its own defence establishment. The site was added to the Queensland Heritage Register on 1 October 2007.