The Saskatchewan River (Cree: kisiskaciwani-sipiy, "swift flowing river") is a major river in Canada, about long, flowing roughly eastward across Saskatchewan and Manitoba to empty into Lake Winnipeg. Through its tributaries the North Saskatchewan and South Saskatchewan, its watershed encompasses much of the prairie regions of central Canada, stretching westward to the Rocky Mountains in Alberta and northwestern Montana in the United States. It reaches to its farthest headwaters on the Bow River, a tributary of the South Saskatchewan in Alberta.