The Attawapiskat River travels a distance of, and has a drainage area of. The source of the river is Attawapiskat Lake at an elevation of. The main rivers flowing into the lake that are thus part of the Attawapiskat River drainage basin are the Marten-Drinking River, the Otoskwin River and the Pineimuta River. There are two outflows from the Attawapiskat Lake into the Attawapiskat River: a southern and a northern channel. The southern channel is named by the Atlas of Canada as the Attawapiskat River, and is the source location listed in the Infobox at right. The northern channel is named by the Atlas of Canada as the North Channel, and is the more easily navigated route for canoeing. The NorthChannel outflow from Attawapiskat Lake is at and consists of two short streams that lead into Windsor Lake. The elevation of the river drops significantly along these two outflow channels, descending from the higher ground of the Canadian Shield to the flatter and more boggy Hudson Bay Lowlands. After a series of rapids, the North Channel rejoins the Attawapiskat River at at an elevation of. The river continues east, and makes a bend to the north at Pym Island at at an elevation of. The Streatfeild River joins from the right at an elevation of, and the outlet river from McFaulds Lake, centre of the Northern Ontario Ring of Fire geological area, joins from the left further downstream at at an elevation of. Further downstream, the river then heads east once again. The Muketei River joins the Attawapiskat from the left at at an elevation of, and the Missisa River joins from the right further downstream at at an elevation of. At at an elevation of the Lawashi Channel begins and takes part of the Attawapiskat's flow into the Lawashi River at a point upstream of that river's mouth at James Bay. The mouth of the Lawashi River is approximately southeast of the mouth of the Attawapiskat. After the Lawashi Channel branching, the main river continues east, past the community of Attawapiskat upstream from the mouth, and exits into the James Bay at the Akimiski Strait, across from Akimiski Island.
Geology
Less than from its mouth, the Attawapiskat has carved out several clusters of spectacular high limestone islands, nicknamed by canoeists the "Birthday Cakes". The formations are unique to the region, the Swampy Cree word for which, tawâpiskâ, gives name to the river. The Attawapiskat kimberlite field lies astride the river.
Economy
Otoskwin/Attawapiskat River Provincial Park includes parts of the river from Attawapiskat Lake to a point just upstream of the confluence with the Muketei River. Since June 26, 2008, the De BeersVictor Diamond Mine, in the Attawapiskat kimberlite field, has operated near the river about west of the community of Attawapiskat. The mine was expected to produce of diamonds a year.
