in Sydney's western suburbs that does not fall into the Parramatta River catchment. As it flows north, it enters a more rural area, with only small settlements on the river. On this stretch it passes Sackville and Lower Portland, where it is joined by the Colo River. The Colo River and its tributaries drain the northern section of the Blue Mountains. From Lower Portland, the Hawkesbury River continues flowing northwards to the small community of Wisemans Ferry where it is joined by the Macdonald River. Here its course turns eastwards and the surrounding landscape gradually becomes steeper and more rugged. At Spencer, Mangrove Creek joins the river from the north. From here to the river mouth, road access to the river is limited to a few points. At Milsons Passage, the river is joined by Berowra Creek from the south. In the area around Brooklyn the river is crossed by the major road and rail services that follow the coast north from Sydney. The river finally reaches the ocean at Broken Bay. From the confluence of the Nepean and Grose Rivers to the sea, the Hawkesbury River has a total length of some . Islands Islands in the Hawkesbury River include, in order going downstream are Barr Island, Milson Island, Snake Island, Peat Island, Spectacle Island, Long Island, Dangar Island and Lion Island. Crossings Despite forming the effective boundary of the metropolitan region of Sydney for its entire length, there are very few fixed crossings of the Hawkesbury River proper. Going downstream, these comprise: In the lower reaches of the river there are also a few passenger ferries that cross the river. These include the Palm Beach Ferry service from Palm Beach to Ettalong and Wagstaffe, and the Hawkesbury River Ferries service from Brooklyn to Dangar Island and Little Wobby. History Aboriginal Australian history A list from 1829 made by Reverend John McGarvie includes the place names used by the Aboriginal people along the river, including the name of the river itself Dyarubbin. An alternative spelling of the Aboriginal name for the river was published as Deerubbun in 1870. The two main Aboriginal tribes inhabiting the area were the Wannungine of the coastal area on the lower reaches (below Mangrove Creek) and the Darkinyung people, whose lands were extensive on the lower Hawkesbury to Mangrove Creek, upper Hawkesbury, inland Hunter and lower Blue Mountains. Also known on the banks of