Lake Nipissing is a
lake in the
Canadian province of
Ontario. It has a surface area of , a mean elevation of above
sea level, and is located between the
Ottawa River and
Georgian Bay. Excluding the
Great Lakes, Lake Nipissing is the third-largest lake in Ontario. It is relatively shallow for a large lake, with an average depth of only . The shallowness of the lake makes for many
sandbars along the lake's irregular shoreline. The lake has many
islands most of which are protected under the Protection of Significant Wetlands scheme, controlled by the Ministry of Natural Resources.