Mystic

About the Mystic Lake Hydroelectric Facility

The Mystic Lake Hydroelectric Project is a two-unit hydro plant on the West Rosebud Creek in the Beartooth Mountains, about 75 miles southwest of Billings, in southern Montana. Completed in 1925, this plant has a generating capacity of 12 megawatts.

Mystic is classified as a “storage generation” project because it uses the water stored in its reservoir to generate electricity. Rowe Dam at Mystic Lake sits at an elevation of about 7,600 feet. The spectacular waterfall at the foot of Mystic Lake is the largest in the Beartooth Mountains.

Learn more about our operations at Mystic Lake

Historic Namesake

Historic Namesake

Mystic Lake is the largest lake in the Beartooth Mountains, and before the construction of the dam, its natural outlet was the high point of Rosebud Falls. 

Now known as "Rowe Dam at Mystic Lake," Rowe dam was renamed in 2022 in honor of retiring NorthWestern Energy CEO Bob Rowe.

A remote location

A remote location

Because of the remote location of Mystic Lake, in the heart of the Beartooth Mountains at an elevation of about 7,600, the way employees reach the dam has evolved over the course of time. 

In 1979, a rockslide took out part of the water flowline and washed out a stretch of the railway line that employees used to reach the dam. The damage was repaired, and a foot bridge was constructed for employees to cross the washed-out section of the rail. Today, workers take the line to the bridge, and cross on foot before re-boarding the upper stretch of the rail line.

The foot trail near the power house offers a popular path to mystic lake and the high country of the Absaroka-Beartooth Wilderness. It is also the start to one of several route to Granite Peak, the highest point in Montana. 

"Golden Kilowatts: Water Power and the Early Growth of Montana"

The book "Golden Kilowatts: Water Power and the Early Growth of Montana" by Butch Larcombe tells the history of Montana's dams.
Learn More Purchase the book online

Historic American Engineering Record (HAER)

The Historic American Engineering Record (HAER) was established in 1969 as one of the Heritage Documentation Programs administered by the National Park Service (NPS) to record the engineering and industrial heritage of the United States. HAER was created through agreements between the NPS, the Library of Congress, and several engineering societies.

HAER documents a variety of engineering and industrial sites, structures and objects. Transportation infrastructure, bridges, mines, industrial buildings/machinery and public utilities are all types of engineering and industrial heritage that have been recorded under this program. The goal of the HAER program is to record the engineering heritage that is subject to being lost due to a variety of factors. These may include technological advancements creating obsolescence, changing regulations surrounding health/environmental/public safety, and development issues. The NPS, through their Heritage Documentation Program, issues the guidelines for HAER documentation and its dissemination.

As part of the FERC licenses for the eleven hydroelectric facilities that NorthWestern Energy own and operate, HAER documentation is conducted when a project or upgrade is determined to have an adverse effect on a facility’s engineering heritage. After the HAER documentation is completed for a particular project or upgrade, NorthWestern Energy submits the documentation to the NPS for review and acceptance. Once accepted, the HAER program coordinates with the Library of Congress to store the document and disseminate it to the public on their website.

Each link below connects to the applicable HAER document available on the Library of Congress website. Visit Historic American Engineering Record (HAER) Documentation to learn more about the HAER documentation conducted at other NorthWestern Energy hydroelectric facilities.