Charles M. Russell High School is a public high school in Great Falls, Montana, in the United States. It is part of the Great Falls Public Schools system. It is one of two public high schools in the city, the other being Great Falls High School. The school opened on September 7, 1965, with about 1,400 students. The school had about 1,515 students enrolled in the 2011–2012 school year. CMR was opened in 1965 and the Rustlers have won 13 Montana state AA football championships, the most of any school in that time period.

Great Falls is the third most populous city in the U.S. state of Montana and the county seat of Cascade County. The population was 60,442 according to the 2020 census. The city covers an area of 22.9 square miles (59 km2) and is the principal city of the Great Falls, Montana, Metropolitan Statistical Area, which encompasses all of Cascade County. The Great Falls MSA's population stood at 84,414 in the 2020 census.