The river begins at the community of
Allanwater Bridge at the confluence of the two branches of the
Brightsand River: the western branch arriving as the outlet from
Kawaweogama Lake and the eastern branch arriving as the outlet from McEwan Lake. The
Canadian National Railway transcontinental main line crosses over a bridge at the point of confluence, and is the location of
Allanwater Bridge railway station, served by
Via Rail transcontinental
Canadian trains. The river flows north and splits into two channels, then recombines, takes in the right tributary Nemo River and reaches Brennan Lake. The river leaves the lake east over Brennan Falls to Granite Lake, and then leaves that lake north over Granite Falls. It continues north over Black Beaver Rapids, Little Sturgeon Rapids and Sturgeon Rapids to reach its mouth at Wabakimi Lake on the
Ogoki River. The Ogoki flows via the
Albany River to James Bay. With the exception of a short stretch at the start, the river lies within
Wabakimi Provincial Park. ==Tributaries==