Railroad logging was an important part of Montana's lumber industry, and the Big Blackfoot Railroad was one of several logging railroads created to sustain the Anaconda Copper Mining Company's sawmill at Bonner. Built by the Chicago, Milwaukee, St. Paul and Pacific Railroad between 1911 and 1936, the line was used almost exclusively by the Anaconda Company. After acquiring 625,000 acres of timber in the Blackfoot River Valley in 1904 to supply lumber and cord wood for mining and smelting operations in Butte and Anaconda, the company harvested about 40 million board feet of lumber annually from its valley property for twenty-eight years, becoming Montana's largest timber producer. This section of railroad grade was constructed in 1934. By the early 1940's, economic depression, war, and the increasing use of trucks to haul lumber caused a sharp decline in the valley's logging industry. Although the Anaconda Company ceased logging operations in the Blackfoot Valley in 1949, the line was not abandoned until 1978. Because the line was never intended to be permanent and was often relocated to take advantage of new timber stands, track was frequently placed directly on the ground without ballast or significant grading, and portions of the old railroad can still be seen adjacent to the highway to the south.