Lake Ontario is similar to Lake Erie in length and breadth (193 miles by
53 miles). Yet with its greater average depth (approximately 283 feet), Lake Ontario holds almost four times the
volume (393 cubic miles) and has a retention time of about 6 years . The drainage basin covers parts of Ontario
and New York, and a small portion of Pennsylvania. Major urban industrial centers, such as Hamilton and
Toronto, are located on its shore. The U.S. shore is less urbanized and is not intensively farmed.
Lake Ontario Figure and Facts:
Length - 193 miles / 311 km.
Breadth - 53 miles / 85 km.
Ave. Depth -
283 ft. / 86 m
Max. Depth - 802 ft. / 244 m.
Volume - 393 cubic miles / 1,640 cubic km.
Water Surface Area
- 7,340 sq. miles / 18,960 sq. km.
Drainage Basin Area - 24,720 sq. miles / 64,030 sq. km.
Shoreline Length (including
islands) - 712 miles / 1,146 km.
Elevation - 243 ft. / 74 m.
Outlet - St. Lawrence River to the Atlantic Ocean
Retention/Replacement Time - 6 years
Name - Champlain first called it Lake St. Louis in 1632. On a Sanson map
in 1656, it remained Lac de St. Louis. In 1660, Creuxius gave it the name Lacus Ontarius. Ontara in Iroquois
means "lake," and Ontario, "beautiful lake."
Ontario, the 14th largest lake in the world, is the smallest of the Great Lakes in surface area. It ranks fourth
among the Great Lakes in maximum depth, but its average depth is second only to Lake Superior. Lake Ontario lies
325 ft (99 m) below Lake Erie, at the base of Niagara Falls. The falls were always an obstacle to navigation into
the upper lakes until the Trent-Severn Waterway, along with the Welland and Erie Canals were built
to allow ships to pass around this bottleneck. The oldest lighthouse on the U.S. side of the Great Lakes was set
up at Fort Niagara in 1818 to aid navigation. The basin is largely rural, with many scenic resort areas. A few
large urban areas, including Ontario's capital city (Toronto), are located on the Canadian shoreline. In 1972-73,
1,000 scientists, engineers and technicians undertook the most extensive survey ever made of a Great Lake.
Great Lakes Atlas, Environment Canada and U.S. Environmental Protection Agency, 1995
Lake Ontario brochure, 1990, Michigan Sea Grant
Cold Water Species