There are five rivers with the name Beaver River in the province of 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....

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

.

The Beaver River in the Regional Municipality of Durham is a tributary of Lake Simcoe

Lake Simcoe

Lake Simcoe is a lake in Southern Ontario, Canada, the fourth-largest lake wholly in the province, after Lake Nipigon, Lac Seul, and Lake Nipissing. At the time of the first European contact in the 17th century the lake was called Ouentironk by the Huron natives...

 and has its mouth at the community of Beaverton

Beaverton, Ontario

Beaverton is a community in Brock Township in the Regional Municipality of Durham, Ontario, Canada.Originally part of Thorah Township in Ontario County, Beaverton was first settled in 1822. The settlement is located on Lake Simcoe at the mouth of the Beaver River...

 at 44°25′56"N 79°09′55"W. The river is sometimes called the Beaverton River.

The Beaver River in in Grey County

Grey County, Ontario

Grey County is a county and census division of the Canadian province of Ontario. The county seat is in Owen Sound. The population was 92,411 in 2006. It is located in the subregion of Southern Ontario named Southwestern Ontario...

 flows from 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...

 to empty into Nottawasaga Bay

Nottawasaga Bay

Nottawasaga Bay is a bay of Lake Huron in Ontario, at the southernmost end of Georgian Bay. Communities on Nottawasaga Bay include Meaford, Collingwood and Wasaga Beach....

, an inlet of Georgian Bay

Georgian Bay

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

, at Thornbury, Ontario at 44°33′54"N 80°26′52"W. The Beaver Valley is a deep wedge on the western side of the escrarpment, formed by a much larger ancestor of this river. A fish ladder

Fish ladder

A fish ladder, also known as a fishway, fish pass or fish steps, is a structure on or around artificial barriers to facilitate diadromous fishes' natural migration. Most fishways enable fish to pass around the barriers by swimming and leaping up a series of relatively low steps into the waters on...

 near Thornbury allows fish to reach spawning

Spawn (biology)

Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...

 areas up river. The river is also a popular recreational canoe

Canoe

A canoe or Canadian canoe is a small narrow boat, typically human-powered, though it may also be powered by sails or small electric or gas motors. Canoes are usually pointed at both bow and stern and are normally open on top, but can be decked over A canoe (North American English) or Canadian...

 route. The Boyne River

Boyne River (Ontario)

There are four rivers named Boyne River in Ontario, Canada.The Boyne River in Grey County flows from above the Niagara Escarpment through Flesherton to join the Beaver River at ; the Beaver River then flows to Georgian Bay...

 joins this river near Eugenia Falls where the Beaver River falls over the escarpment. There is a hydroelectric plant at these falls; Lake Eugenia was formed when the river was dammed to control river flow. The Beaver River valley is home to a number of downhill ski clubs. The river's drainage basin

Drainage basin

A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...

 is under the auspices of Grey Sauble Conservation.

There are two rivers by the name of Beaver River in Kenora District

Kenora District, Ontario

Kenora District is a district and census division in Northwestern Ontario, Canada. It was created in 1907 from parts of Rainy River District. It is, geographically, the largest division in that province; at 407,192.66 km2 it comprises almost 38 percent of the province's land area...

:

• one is a major tributary of the Severn River
  Severn River (northern Ontario)
  The Severn River is a river in northern Ontario. The northern Ontario river has its headwaters near the western border of the province. From the head of the Black Birch River, the Severn River is long and its drainage basin is 102,800 km² , a small portion of which is in Manitoba...
  
   in far northwestern Ontario
  Northwestern Ontario
  Northwestern Ontario is the region within the Canadian province of Ontario which lies north and west of Lake Superior, and west of Hudson Bay and James Bay. It includes most of subarctic Ontario. Its western boundary is the Canadian province of Manitoba, which disputed Ontario's claim to the...
  
   and has its mouth at 55°55′21"N 87°48′48"W.
• the other is a tributary of the Kapiskau River and has its mouth at 52°38′41"N 82°24′14"W.

The Beaver River in Thunder Bay District

Thunder Bay District

Thunder Bay District is a district and census division in Northwestern Ontario in the Canadian province of Ontario. The district seat is Thunder Bay....

 is a tributary of the Firesteel River

Firesteel River (Ontario)

The Firesteel River is a river in Thunder Bay District, northwestern Ontario, Canada. It flows from Trap Lake, east of the Canadian National Railway location of George and north of the community of Upsala, southwest under the Canadian National Railway, the Canadian Pacific Railway mainline and...

. It begins north of Ontario Highway 17 and has its mouth at 49°03′02"N 90°46′48"W.