The surface of Waswanipi Lake is usually frozen from early November to mid-May, however, safe ice circulation is generally from mid-November to mid-April.

An island in the lake was historically the location of a Cree summer village, also known by the name of Waswanipi.

The toponym Waswanipi Lake was formalized on December 5, 1968, at the Bank of Place Names of the Commission de toponymie du Quebec.

Four members of the Cree Indians had been hospitalized in Montreal with levels of mercury in their body 10 times higher than the national average.

According to the government, the poisoning of the waters was due to the region's rich mineral content of geological strata, yet the result was a direct threat to the Indians' way of life.