In 1913, as the Tri-State district expanded, lead and zinc ore were discovered on Harry Crawfish's claim and mining began. A town site developed overnight around the new workings and was named Picher in honor of O. S. Picher, owner of Picher Lead Company. The city was incorporated in 1918, and by 1920, Picher had a population of 9,726. Peak population occurred in 1926 with 14,252 residents. Mining ceased in 1967. The contaminated water from some 14,000 abandoned mine shafts, 70 million tons of mine tailings, and 36 million tons of mill sand and sludge remained as a huge environmental cleanup problem. As a result of national legislation to identify and remediate such environmentally hazardous sites, in 1980 the area was designated as part of the Tar Creek Superfund site.