[4][5] The earliest documentation of the lake's name is "Tekamamiwen" (shown in French transliterated as "Lac de Tecamamiouen" on the Ochagach map (c.

[7][8] He said that the lake was also known as "Ouichichick" (Ojibwe word Gojijiing or Cree Kocicīhk, both meaning "at the place of inlets").

Winter access to Rainy Lake by car is provided by an ice road maintained by the National Park Service of the United States.

Popular winter sports include ice fishing, cross-country skiing, snowshoeing, and snowmobiling.

The relevant law enforcement agencies of each country are responsible for the portions of the lake within their respective borders.

Boaters and fishermen must be aware of the requirements imposed by relevant jurisdictions while traveling or fishing on Rainy Lake (see External links).

The level of Rainy Lake is controlled at the hydro-electric power houses of the international dam that spans the Rainy River between International Falls and Fort Frances, at two water-control dams located at Kettle Falls where the outflow from Namakan Lake enters Rainy Lake, and at the Sturgeon Falls Generating Station located on the Seine River.

The companies that own and operate the powerhouses (Boise Paper on the US side and H2O Power Limited Partnership on the Canadian side) are responsible for maintaining lake level and flow changes from the dams within normal ranges, subject to regulatory oversight by the International Rainy-Lake of the Woods Watershed Board (IRLWWB).