Offshore exploration in the Great Lakes region has resulted in a small but growing industry on the Canadian side of the international boundary. Approximately 35 billion cu. ft. of natural gas has so far been produced from beneath the waters of shallow Lake Erie, where offshore activity has been concentrated. The 5 Great Lakes make one of the largest fresh-water drainage systems in the world, and it is of interest that the underlying oil and gas reserves should now be tapped. The lakes are an important natural asset to the 71 million population living in the province of Ontario in Canada and in the 8 states of the U.S.A.; all of which touch on their shores. Lake Erie and the southern part of Lake Huron have particularly attractive geological possibilities; Lake Michigan. and Lake Ontario have geological possibilities as well, with those areas onlapping the Precambrian Shield to a progressively less degree, approaching the Shield; Lake Superior is the deepest and is unattractive, lacking adequate Paleozoic representation. So far Lake Erie and Lake St. Clair have been the only areas made available for drilling; the other lakes are suitably shallow for drilling with present tower-equipment only along their perimeters. Water depths, greater than the arbitrary 108-ft. maximum which is suggested here for bottom-based towers currently in use, could be handled by more elaborate and expensive towers, by drilling barges, or by drilling vessels of the type used in Lake Erie in 1960. Two hundred ninety-three wells have been drilled offshore in Lake Erie and Lake St. Clair to date, with 2 of these in the United States opposite Pennsylvania.