Lake Nipissing, Large freshwater lake in Northern Ontario, Canada

Lake Nipissing covers 873 square kilometers with irregular shorelines and numerous sandbars, shaped by its shallow average depth of 4.5 meters. This shallow character creates the visual and physical qualities that define the water body.

French fur trader Étienne Brûlé arrived at the lake in 1610, followed by Jean Nicolet who operated a trading post on its shores until 1633. These early European contacts made it an important route for commerce.

The name comes from the Ojibwe word 'nibiinsing', meaning 'at little water', and local Indigenous communities call it Gichi-nibiinsing-zaaga'igan. These names reflect the deep connection that Anishinaabe peoples have maintained with this water for generations.

The lake holds 44 fish species; anglers mostly target walleye, smallmouth bass, muskie and northern pike, and several stocking associations work to manage the walleye population. The average depth is only 4.5 m, so shallow, irregular shores produce many sandbars; the deepest point, 64 m, lies near the French River mouth off Blueberry Island. Most islands fall under the Ministry of Natural Resources and Forestry's wetlands protection scheme.

Lake Nipissing sits in the Ottawa-Bonnechere Graben, a rift valley that opened about 175 million years ago. Its two volcanic pipes, at the Manitou Islands and Callander Bay, formed from violent eruptions of deep-origin volcanoes. The lake is also the third-largest entirely within Ontario.