McArthur Lake is a reservoir in Boundary County, Idaho, USA. It gives its name to the McArthur Lake Wildlife Corridor, which provides a bridge for wildlife to migrate between two mountainous areas. The reservoir and surrounding wetlands are rich in bird life, and are protected by the McArthur Lake Wildlife Management Area. There has been discussion about removing the dam that impounds the reservoir, which would improve the wetlands so they would support larger numbers of game birds, and would also improve the quality of water downstream.