The Battle of Lake Whatcom was a month-long campaign during the Alaskan War to dislodge Alaskan defensive positions in the Chuckanut Mountains south of Bellingham in what is the present-day U.S. state of Washington. Fought in August of 1885, the fighting marked the beginning of the long and arduous rollback of Alaskan troops from American territory and was the first offensive victory for the United States in the Oregon Theater.