Its headwaters rise on the sandplains below Mount Madden and flow in a southerly direction, crossing the South Coast Highway approximately 20 kilometres (12 mi) west of Ravensthorpe, entering the Fitzgerald River National Park and veering eastward to follow a fault-line in the quartzite rocks around the eastern end of the Barren Range. The river finally discharges into Culham Inlet and, when the inlet is open to the ocean, into the Southern Ocean.
There are six tributaries, including West River, Jackilup Creek, Yarracarrup Creek and Kybalup Creek.
Phillips River flows for only a short time each year, mostly during the winter months in the middle of the year. The river water is naturally saline but varies from almost fresh to more saline then seawater.
From 1892, it was the site of a gold rush. A de facto town, known initially as Phillips River, sprang up. In 1901, the town was gazetted under the name Ravensthorpe.
^Chapman, A. L. (Andrew Lewis), 1931-; Parker, Kaylene; Western Australia. Water and Rivers Commission; Natural Heritage Trust (Australia); Ravensthorpe Land Conservation District Committee (2003), Phillips River action plan, Water and Rivers Commission, ISBN978-1-920849-19-1{{citation}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)