In the 1820s, after lead ore or Galena was discovered in the area, a mining boom took the area by storm. The mining district eventually encompassed a significant portion of southwest Wisconsin, including the counties of Grant, Iowa, and Lafayette; and Jo Daviess County, Illinois. These were central to the exploitation and mining of lead and zinc ore. The Galena, Illinois mining district, an area south of Platteville, had been known to many for years. Beginning in 1825, demand drove up the price of lead and the Platteville economy flourished. The "grey gold" (a common nickname for lead ore) brought development of businesses and schools in the town. Platteville's landscape was shaped by the mining that helped build the town. Mineral holes abounded everywhere.