Hinchinbrook is the high spine of an old coastal range, built from late Palaeozoic granite uplifted as great fault blocks while the land between them sank. When the last Ice Age ended around 18,000 years ago and the sea climbed, it flooded the valley behind the range and severed the island from the mainland - the narrow Hinchinbrook Channel that now separates them is the drowned valley of the Herbert River. The peaks that survived are dramatic. Mount Bowen crowns the island at 1,121 metres, with The Thumb, Mount Diamantina and Mount Straloch all rising above 900. Curiously, no coral reefs grow in the waters immediately around the island, most likely because so much fresh water pours off its rain-soaked slopes.

The wildness here is not only vertical. Along the western shore, the Hinchinbrook Channel is fringed by some of the most robust mangrove estuaries in Australia - roughly 164 square kilometres of them - a labyrinth of tidal forest where saltwater crocodiles rule and sea kayakers are warned off. In the shallow tidal flats of Missionary Bay, at the island's north, dugongs graze offshore seagrass beds, and the beach stone-curlew thrives along sands where, crucially, vehicles are banned. The great dune barrier at Ramsay Bay tells its own slow story: built of wind-blown sand in two episodes, the older dunes partly drowned by a rising sea thousands of years ago, the newer ones laid down within the last nine centuries.

Aboriginal people lived on this island for thousands of years; shell middens and stone fish traps still mark their presence along the shores. Early contact with British navigators in 1815, 1819 and 1843 was, by the sailors' own accounts, largely friendly. That did not last. After the township of Cardwell was founded across the channel in 1864, relations collapsed. Native Police expeditions swept the island - in 1867, and again in 1872, when troopers hunting the killers of two fishermen carried off three Aboriginal children; a visitor recorded that one of the children was assaulted by police, and that settlers spoke openly of slaughtering whole camps of men, women and children. Through such violence the island's people were reduced to a handful of survivors. A missionary who arrived in 1874 abandoned his post, having learned of the massacres and met almost no one in nine months. These were not statistics. They were families, custodians of a country they had held for millennia, and their descendants - the Bandjin and Girramay - help care for Munamudanamy still.

Modern Hinchinbrook is defined by a single trail. The 32-kilometre Thorsborne Trail traces the island's eastern coast, threading rainforest, creek crossings, beaches and the foot of Mount Bowen, and is widely rated among the finest wilderness walks in Australia. Numbers are strictly limited and camping is by permit only, which is why the trail stays wild. It carries the name of Arthur Thorsborne, who with his wife Margaret spent decades defending this coast - the couple began annual surveys of the migratory pied imperial-pigeon colonies on the nearby Brook Islands back in 1965. Their fight helped keep development off the island. The reward for walking quietly through what they protected can be a giant tree frog in the leaf litter, a curlew on an empty beach, or simply the silence beneath those granite peaks.