Significant for playing a huge part in the copper production during the early 1900s, the Butte-Anaconda District holds the record in all of the US National Historic Landmark Districts ever. It was declared as a NHL in 1961, and was expanded in 2006, including some parts of Anaconda, Walkerville, and the bed of Butte.

The area of the Butte-Anaconda Historic District was once the biggest producer of copper in the country. It was so massive that they were able to supply almost 1/3 of the world?s copper demands. The mines were also historic for being the place where the forerunners of the Western Federation of Miners, the Industrial Workers of the World, and the Congress of Industrial Organizations were formed.