Aroostook War, Feb.-May, 1839, border conflict between the United States and Canada. In 1838, Maine and New Brunswick both claimed territory left undetermined on the U.S.-Canadian border, including the valley of the Aroostook River. Maine farmers were interested in the valley's farmlands, and when New Brunswick sent Canadian lumbermen to do logging there, Maine authorities raised a force to eject them. New Brunswick asked for British regular troops and full-scale fighting seemed imminent, but Gen. Winfield Scott, who had been sent to the area with a small U.S. force, managed to reach an agreement (Mar., 1839) that prevented trouble. The boundary was later settled by the Webster-Ashburton Treaty (1842).