Water quality of the lake is important for ensuring safe recreational use an maintaining this essential economic and ecological resource.

The Purcell Lobe of the Cordilleran Ice Sheet flowed south from Canada, carving the basin of present-day Lake Pend Oreille and damming the Clark Fork river.

[3] Large eddy bars formed downstream from bedrock obstructions, thereby damming tributary valleys and creating lakes.

Lake Coeur d'Alene was an important source of large trout, salmon, whitefish, and water potato.

[6] The Schitsu’umsh tribe has filed multiple lawsuits (1991, 2008, and 2011) to protect the quality of the water and provide funds for hazardous waste clean-up.

[citation needed] Also, steamboats on the bottom resulted from being burned and sunk as wrecks when they were no longer of use to ferry people around the lake.

[citation needed] The Coeur d'Alene Tribe owns the southern third of Lake Coeur d'Alene and its submerged lands as part of its reservation, in addition to miles of the Saint Joe River and its submerged lands, all of which the United States holds in trust for the tribe.

Lake water has elevated levels of zinc, lead, and cadmium,[13] but is generally considered safe for swimming.

Instead, a Lake Management Plan was developed, to be implemented by the State of Idaho and the Coeur d'Alene (Schitsu’umsh) Tribe.

As concentrations of zinc in the lake water decrease due to pollution remediation efforts in the Silver Valley, eutrophication may become more likely.

[13] However, warmer lake water temperatures due to climate change could make eutrophication more likely, and a better understanding of sources of phosphorus in the watershed is needed.

[18] Bull trout, westslope cutthroat, and whitefish were all native to the lake, but their populations have declined and in some cases they are found only in the tributaries.

[17] Lake Coeur d'Alene is a popular tourist site for many people during the summer, offering great beaches and scenic views.

A popular seasonal activity is viewing the bald eagles as they feed on the kokanee in the lake, mainly from the Wolf Lodge Bay.