Mississippi Lake is located in Lanark County. Ontario’s Mississippi River flows northeast and north through the lake, with Cranberry Creek, McCrearys Creek, and McGibbon Creek draining into the lake from neighbouring forests and properties. The lake is distinctive in Ontario, as it borders the Canadian Shield on the north shore.

Mississippi Lake is a premier fishing stop, with an average depth of 9 feet, bottoming out at approximately 30 feet. Walleye remains a popular catch. Shore anglers, especially young children, delight in being able to bring up Largemouth Bass and Smallmouth Bass, Crappie, Pike, Bluegill and Sunfish.