Mining operators in the San Juan mountain area of Colorado formed the San Juan District Mining Association (SJDMA) in 1903, as a direct result of a Western Federation of Miners proposal to the Telluride Mining Association for the eight-hour day, which had been approved in a referendum by 72 percent of Colorado voters.

[4] The SJDMA refused to consider any reduction in hours or increase in wages, helping to provoke a bitter strike.

The Smuggler-Union, Tomboy, and Liberty Bell mines combined produced over a hundred tons of gold by 1920, third in the state of Colorado.

Since 1988, the county has become one of the most Democratic in Colorado and the nation, largely due to the presence of the Telluride Ski Resort and the influx of liberal-minded voters in the 1960s and 1970s.

In the 2000 presidential election, San Miguel County was Green Party candidate Ralph Nader's best countywide performance in the country with 17.2% of the vote.