Border dispute over Maine's northern territory.
A confrontation in 1838-39 between the United States and Great Britain over the international boundary between British North America (Canada) and Maine. It is called a war because not only were tensions high, but troops were raised and armed on both sides and marched to the disputed border. Roughly around 12,000 soldiers were mobilized BUT no fighting took place. President Martin Van Buren sent General Winfield Scott to work out a compromise. A neutral area was created and the controversy gradually died down.
It resulted in an ‘official’ border between Maine and Canada and established the Webster-Ash Treaty.