Potosi was the prototypical lead mining community. Early settlers arrived in the 1820s, before the Black Hawk War, and scoured the hollows and ravines for signs of lead. While it was known as early as 1829 that lead sulfide deposits were abundant, little mining occurred because conditions were not stable and, well, technically, Americans had no legal title to the land until after the Black Hawk War. In 1832, Willis St. John and Isaac Whitaker moved in. St. John founded a mine and got rich very quickly. He found a cave rife with lead and also with snakes, which is why the area around his cave became known as Snake Hollow. He died in 1853 a pauper, however, after losing all his money in a bank crisis. Mining took off full bore around 1835, and Snake Hollow boomed.
Separate communities grew up in different sections of the hollow. Lafayette was south of Snake Hollow on the bank of the Grant River in Grant Slough; that town was laid out in 1837. Van Buren was located in the lower portion of the hollow (near the Potosi Brewery); settlers began arriving in 1837 and the town was laid out in 1839. Van Buren had the first post office but Lafayette had the steamboat landing (the “Port of Potosi”) and ferry service to Iowa.
In 1839, these disparate communities consolidated into a single town called Potosi; businesses quickly moved toward the new center and out of Lafayette and Van Buren. By the time Potosi incorporated in 1841, the town claimed 1,300 residents and within a few years it had an economy nearly as large as Galena’s. The bulk of the town was concentrated along a three-mile hollow pierced with a single road. Rain often turned the road into a dangerous creek (it can still happen after torrential rain).
Like Galena, the decline of lead mining had a dramatic impact on the town’s economy. Between 1849 and 1852, scores of miners abandoned Potosi for the California gold rush, leaving in two waves. Potosi weathered the first wave, but the second one, fueled in part by a cholera epidemic in 1852, devastated the town. At the peak of the exodus, ferries were so busy that emigrating miners had to wait up to five days to cross the Mississippi. Another factor in Potosi’s decline was the fact that Grant Slough, the area that had the steamboat port, filled with silt because of deforestation, making steamboat landings impossible. Unable to dock at Potosi, river commerce shifted south to Dunleith (East Dubuque) and north to Cassville.
The town emptied out so quickly that incorporation was repealed in 1854. Even the town clerk’s books vanished, taking with it all official record of village life before 1854. The Chicago, Burlington, and Northern railroad reached Potosi in 1884, injecting new life back in the village. Potosi reincorporated in 1887 but by 1895 the town’s population had fallen to 454 or roughly one-quarter of what it was at its peak.
Potosi has never again experienced the economic prosperity it knew during the lead mining years, but it settled into the life of a small town with a farm-centered economy. Today, many of its residents commute to jobs in other towns, although tourism is becoming a more important part of the local economy.