Formed by the confluence of the East Branch and West Branch of the river, the Saint Patricks River rises below Mount Jack within the Errinundra National Park, and flows generally north northwest, before reaching its confluence with the Big River, in remote country southwest of the locality of Malinns in the Shire of East Gippsland. The river descends 184 metres (604 ft) over its 9-kilometre (5.6 mi) course.[2]