Kerr Dam is a three-unit hydroelectric plant on the Flathead River about five miles southwest of Polson and the natural outlet of Flathead Lake. The units have a total generating capacity of 196 megawatts. (One megawatt can satisfy the average energy needs of 750 households.)

The dam, which began operation in 1938, is 541 feet long and 205 feet high. Its installation raised the level of Flathead Lake by 10 feet over the natural lake outlet. The dam’s 28-mile-long reservoir has a storage capacity of 1.2 million acre-feet. Kerr Dam is classified as a “storage generation” project because it uses the water stored in its reservoir to generate electricity.

Flathead Lake, which lies in the Flathead Valley of northwest Montana, is the largest natural freshwater lake west of the Mississippi. The lake is 28 miles long, up to 15 miles wide and more than 300 feet deep.