Sandon River, an open mature wave dominated, barrier estuary, is located in the Northern Rivers region of New South Wales, Australia. Sandon River rises of the eastern slopes of the Summervale Range, west of Blue Gum Flat and flows generally northeast before reaching its mouth at the Coral Sea of the South Pacific Ocean below Sandon Bluffs; descendi…Sandon River, an open mature wave dominated, barrier estuary, is located in the Northern Rivers region of New South Wales, Australia. Sandon River rises of the eastern slopes of the Summervale Range, west of Blue Gum Flat and flows generally northeast before reaching its mouth at the Coral Sea of the South Pacific Ocean below Sandon Bluffs; descending 37 metres over its 16 kilometres course.