Aroostook River

The Aroostook River is a 112-mile-long tributary of the Saint John River, spanning parts of Maine and New Brunswick. Its name originates from the Malecite term "Wool-ahs-took," meaning "good river for everything." The river's basin is the largest sub-drainage area of the Saint John River.

In the late 1830s, the region around the Aroostook River was the site of the Aroostook War, a boundary dispute between the United States and the United Kingdom. Geographically, the river begins in northeastern Maine from the confluence of Millinocket Stream and Munsungan Stream in Penobscot County. It flows through Aroostook County, passing through Ashland, north of Presque Isle, and east of Caribou, before joining the Saint John River in New Brunswick.

The U.S. government operates two flow gauges on the river: one near Masardis, Maine, with a watershed of 892 square miles, and another at Washburn, Maine, covering 1,654 square miles. The maximum flows recorded are 29,500 cubic feet per second at Masardis and 49,500 cubic feet per second at Washburn, while minimum flows are 41 and 75 cubic feet per second, respectively. Floods, often caused by ice dams, have occurred frequently, notably in 1999, 2003, and 2004.

The river supports a small run of Atlantic salmon, with an average return of 17 to 30 adults annually from 1998 to 2001. Additionally, the International Appalachian Trail runs alongside the river for several miles, offering hikers opportunities to cross international boundaries near Fort Fairfield, Maine.