The Northwest Branch Saint John River is a 15.5-mile-long (24.9 km) river primarily in Aroostook County, Maine. Its origin (46°42′04″N69°59′55″W) is Lac Frontière in Quebec, Canada. After crossing the Canada – United States border, the Northwest Branch runs south close to the border until it picks up its tributary, the Daaquam River, which also flows out of Canada.