In the far west, where Cambodia runs up against Thailand, the map goes green and stays that way. This is Koh Kong, the gateway to the Cardamom Mountains, one of the largest and least-disturbed rainforests in Southeast Asia, and a coast of river mouths and mangrove that the beach crowds have never really reached.
A frontier of green
Koh Kong town is a quiet border place, more useful than lovely, but it is the doorway to something remarkable. Behind it the Cardamoms rise in wave after wave of jungle, cut by wide, slow rivers and loud with birds and gibbons. This is one of the wildest corners of the country, home to elephants, hornbills and, somewhere in its depths, a few clouded leopards, and to the conservation projects fighting to keep it that way.
On the water
The way to feel the place is from a boat. Rivers carry you between walls of forest, past the occasional fishing hamlet and out towards islands and empty beaches. Mangrove channels thread the estuaries, and the long Koh Kong Island, the country's largest, keeps a string of near-deserted beaches on its seaward side for those willing to make the trip.
A different kind of coast
This is not the powder-sand, cocktail-bar coast of the southern islands. It is wetter, wilder and greener, a place for kayaks and boat trips and nights listening to the forest rather than a beach playlist. That is exactly its appeal. Here the headline act is the landscape itself, still mostly intact, still mostly quiet.
How to be here
Come with time and a sense of adventure. Base yourself at one of the river lodges, go out early with a local boatman, and let the rainforest set the agenda. Koh Kong rewards the traveller who treats wildness as the destination rather than the backdrop.