Trigg Island is a small "island" off the coast of the suburb of Trigg in Perth, Western Australia. It is named after Henry Stirling Trigg, Superintendent of Public Works in the Colony of Western Australia from 1838 to 1851.Trigg Island is a small rocky aeolianite limestone remnant of Pleistocene dunes, better characterised as an outcrop than an island, and as such is typical of the Perth coast.