A single historic placard, easily missed driving through, is the only indication of what happened on Blair Mountain, an isolated, rugged area in Logan County and the site of the largest labor uprising in United States history. In August 1921, an estimated 10,000 to 20,000 coal miners went to war there with an opposing army made up of about 3,000 local law enforcement, company-hired agents and mine guards, protesting deadly working conditions, low wages and brutal violence against union members. The Battle of Blair Mountain came to an end when U.S. President Warren Harding sent in federal troops to intervene. Historians say the West Virginia mine wars lasted nearly a decade -1912 to 1921 – but the struggle between coal miners and coal operators over the rights and safety of the workers has existed since the industry began.