The Commission publishes Special Reports at different intervals to update the geographical coordinates of a section of the boundary and to gather information on the maintenance of a section.

• Special Report 1 - Source of the St. Croix River to the mouth of the St. Francis River, 1956
• Special Report 2 - Mouth of Niagara River to the head of the St. Clair River,1957
• Special Report 3 - Source of the St. Croix River to the Atlantic Ocean, 1962
• Special Report 4 - Arctic Ocean to Mount St. Elias, 1966
• Special Report 5 - St. Lawrence River, 1967
• Special Report 6 - St. Francis River to the St.Lawrence River, 1983
• Special Report 7 - St. Lawrence River to Lake Superior, 1986
• Special Report 8 - Southwest and South Lines, 2017
• Special Report 9 - Southwest Branch of the St. John River, 2017