Black Bay Peninsula is a volcanic peninsula

Peninsula

A peninsula is a piece of land that is bordered by water on three sides but connected to mainland. In many Germanic and Celtic languages and also in Baltic, Slavic and Hungarian, peninsulas are called "half-islands"....

 in Unorganized 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....

 in Northwestern

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...

 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...

, located on the North Shore

North Shore (Lake Superior)

The North Shore of Lake Superior runs from Duluth, Minnesota, United States, at the southwestern end of the lake, to Thunder Bay and Nipigon, Ontario, Canada, in the north to Sault Ste. Marie, Ontario, in the east...

 of Lake Superior

Lake Superior

Lake Superior is the largest of the five traditionally-demarcated Great Lakes of North America. It is bounded to the north by the Canadian province of Ontario and the U.S. state of Minnesota, and to the south by the U.S. states of Wisconsin and Michigan. It is the largest freshwater lake in the...

. It separates Black Bay and Nipigon Bay and consists of over 300 flood basalt

Flood basalt

A flood basalt or trap basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava. Flood basalts have occurred on continental scales in prehistory, creating great plateaus and mountain ranges...

 lava flows. Porphyry Island

Porphyry Island

Porphyry Island is an island in Unorganized Thunder Bay District in northwestern Ontario, Canada. It is the last island in a chain stretching south west of the Black Bay Peninsula in Lake Superior...

, an island entirely encompassed within Porphyry Island Provincial Park

Porphyry Island Provincial Park

Porphyry Island Provincial Park is a remote, non-operating protected area in Unorganized Thunder Bay District in northwestern Ontario, Canada. It is located on Porphyry Island off the tip of the Black Bay Peninsula on the North Shore of Lake Superior...

, lies off the tip of the peninsula. A 49 square kilometres (19 sq mi) portion of the peninsula has been set aside as the Black Bay Peninsula Enhanced Management Area.