Huron, the second largest of the Great Lakes of North America, including Georgian Bay and the channel north of Manitoulin Island, which are always associated with it. It lies between the parallels of 43° and 46° 20′ N. and between the meridians of 80° and 84° W., and is bounded W. by the state of Michigan, and N. and E. by the province of Ontario, Georgian Bay and North Channel being wholly within Canadian territory. The main portion of the lake is 235 m. long from the Strait of Mackinac to St Clair river, and 98 m. wide on the 45th parallel of latitude. Georgian Bay is 125 m. long, with a greatest width of 60 m., while North Channel is 120 m. long, with an extreme width of 16 m., the whole lake having an area of 23,200 sq. m. The surface is 581 ft. above the sea. The main lake reaches a depth of 802 ft.; Georgian bay shows depths, especially near its west shore, of over 300 ft.; North Channel has depths of 180 ft. Lake Huron is 20 ft. lower than Lake Superior, whose waters it receives at its northern extremity through St. Mary river, is on the same level as Lake Michigan, which connects with its north-west extremity through the Strait of Mackinac, and is nearly 9 ft. higher than Lake Erie, into which it discharges at its south extremity through St Clair river.
On the mainland, the north and east shores are of gneisses and granites of archaean age, with a broken and hilly surface rising in places to 600 ft. above the lake and giving a profusion of islands following the whole shore line from the river St Mary to Waubaushene at the extreme east end of Georgian bay. Manitoulin Island and the Saugeen Peninsula are comparatively flat and underlaid by a level bed of Trenton limestone. The southern shores, skirting the peninsula of Michigan, are flat. The rock formations are of sandstone and limestone, while the forests are either a tangled growth of pine and spruce or a scattered growth of small trees on a sandy soil. This shore is indented by Thunder bay, 78 sq. m. in area, and Saginaw bay, 50 m. deep and 26 m. wide across its mouth.
The chief tributaries of the lake on the U.S. side are Thunder bay river, Au Sable river and Saginaw river. On the Canadian side are Serpent river, Spanish river, French river, draining Lake Nipissing, Muskoka river, Severn river, draining lake Simcoe, and Nottawasaga river, all emptying into Georgian bay and North Channel, and Saugeen and Maitland rivers, flowing into the main lake. These have been or are largely used in connexion with pine lumbering operations. They, with smaller streams, drain a basin of 75,300 sq. m.
There is a slight current in Lake Huron skirting the west shore from inlet to outlet. At the south end it turns and passes up the east coast. There is also a return current south of Manitoulin Island and a current, sometimes attaining a strength of half a knot, passes into Georgian bay through the main entrance. Ice and navigation conditions and yearly levels are similar to those on the other Great Lakes (q.v.).
Practically all the United States traffic is confined to vessels passing through the main lake between Lakes Superior and Michigan and Lake Erie, but on the Canadian side are several railway termini which receive grain mostly from Lake Superior, and deliver mixed freight to ports on that lake. The chief of these are Parry Sound, Midland, Victoria Harbour, Collingwood, Owen Sound, Southampton, Kincardine, Goderich and Sarnia, at the outlet of the lake. The construction of a ship canal to connect Georgian bay with Montreal by way of French river, Lake Nipissing and Ottawa river began in 1910. A river and lake route with connecting canals, in all about 440 m. long, will be opened for vessels of 20 ft. draught at a cost estimated at £20,000,000 saving some 340 miles in the distance from Lake Superior or Lake Michigan to the sea.
There is a large fishing industry in Lake Huron, the Canadian catch being valued at over a quarter million dollars per annum. Salmon trout (Salvelinus namaycush, Walb.) and whitefish (Coregonus clupeiformis, Mitchill) are the most numerous and valuable. Amongst the islands on the east shore of Georgian bay, which are greatly frequented as a summer resort, black bass (micropterus) and maskinonge (Esox nobilior, Le Sueur) are a great attraction to anglers.
See Georgian Bay and North Channel Pilot, Department of Marine and Fisheries (Ottawa, 1903); Sailing Directions for Lake Huron, Canadian Shore, Department of Marine and Fisheries (Ottawa, 1905); Bulletin No. 17, Survey of Northern and North-Western Lakes, United States, War Department (Washington, 1907); U.S. Hydrographic Office Publication, No. 108 C. Sailing Directions for Lake Huron, &c. U.S. Navy Department (Washington, 1901).
