Nottawasaga Bay is a bay

Bay

A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...

 of Lake Huron

Lake Huron

Lake Huron is one of the five Great Lakes of North America. Hydrologically, it comprises the larger portion of Lake Michigan-Huron. It is bounded on the east by the Canadian province of Ontario and on the west by the state of Michigan in the United States...

 in Ontario

Ontario

Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, at the southernmost end of Georgian Bay

Georgian Bay

Georgian Bay is a large bay of Lake Huron, located entirely within Ontario, Canada...

. Communities on Nottawasaga Bay include Meaford

Meaford, Ontario

Meaford is a Canadian municipality in Grey County, Ontario. Meaford is located on Nottawasaga Bay, a sub-basin of Georgian Bay, in southern Ontario....

, Collingwood

Collingwood, Ontario

Collingwood is a town in Simcoe County, Ontario, Canada. Geographically, it is situated on Nottawasaga Bay at the southern point of Georgian Bay.-History:...

 and Wasaga Beach

Wasaga Beach, Ontario

Wasaga Beach is a town in Simcoe County, Ontario, Canada. It is a popular four-season tourist destination situated on Nottawasaga Bay at the southern end of Georgian Bay approximately two hours north of Toronto, and abuts, to the west, the town of Collingwood...

.

The western shore of Nottawasaga Bay is determined by the Niagara Escarpment

Niagara Escarpment

The Niagara Escarpment is a long escarpment, or cuesta, in the United States and Canada that runs westward from New York State, through Ontario, Michigan, Wisconsin and Illinois...

, which reaches Nottawasaga Bay between Thornbury and Meaford

Meaford, Ontario

Meaford is a Canadian municipality in Grey County, Ontario. Meaford is located on Nottawasaga Bay, a sub-basin of Georgian Bay, in southern Ontario....

. The southern shore is flat limestone plain, with cedar marshes. The Nottawasaga River

Nottawasaga River

The Nottawasaga River is a river in southern Ontario, Canada. Its headwaters are located on the Niagara Escarpment and Oak Ridges Moraine. It flows through the Minesing Swamp, recognized as a wetland of international significance , and empties into Nottawasaga Bay, an inlet of Georgian Bay, at...

 flows into Georgian Bay near the southern end of the bay, and from the estuary

Estuary

An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

onward to the east the shore is predominantly sand dunes and marshes created by the strong predominant northwest winds. This part of Nottawasaga Bay is heavily built up with summer homes.

Nottawasaga Bay is one of Ontario's busiest tourism areas, but recreational use has taken a toll on it. Pollution from cottages, towns, industry and agriculture have caused a noticeable decline in water quality in recent years, resulting in some beach closings.