(a) Sector Sault Ste. Marie's Marine Inspection Zone and Captain of the Port Zone comprise all navigable waters of the United States and contiguous land areas within an area starting from a point at latitude 44°43′00″ N on the international boundary within Lake Huron; proceeding due west to longitude 85°40′00″ W; thence northwest to the eastern shore of Lake Michigan at latitude 45°01′00″ N; thence northwest to latitude 45°22′30″ N, longitude 86°19′00″ W; thence northeast to latitude 45°41′00″ N, longitude 86°06′00″ W; thence northwest to latitude 46°20′00″ N, longitude 87°22′00″ W; thence west to the Minnesota-North Dakota boundary at latitude 46°20′00″ N, longitude 96°36′30″ W; thence north along the Minnesota-North Dakota boundary to the intersection of the Minnesota-North Dakota boundary and the international boundary at latitude 49°00′02″ N, longitude 97°13′46″ W; thence east along the international boundary to the starting point; and in addition, all the area described in paragraph (b) of this section.

(b) The boundaries of the MSU Duluth Marine Inspection and Captain of the Port Zones comprise all navigable waters of the United States and contiguous land areas within an area starting at a point latitude 46°20′00″ N, longitude 88°30′00″ W, proceeding west to the Minnesota-North Dakota boundary at latitude 46°20′00″ N, longitude 96°36′30″ W; thence north along the Minnesota-North Dakota boundary to the intersection of the Minnesota-North Dakota boundary and the international boundary at latitude 49°00′02″ N, longitude 97°13′46″ W; thence east along the international boundary to a point at latitude 47°59′23″ N, longitude 87°35′10″ W; thence south to a point near Manitou Island Light at latitude 47°25′09″ N, longitude 87°35′10″ W; thence southwest to a point near the shore of Lake Superior at latitude 46°51′51″ N, longitude 87°45′00″ W; thence southwest to the point of origin.