Saltpeter Cave on the right bank of the Meramec River, one hundred miles upstream from its confluence with the Mississippi River, was long known for cave dirt enriched by bat guano that could be processed into potassium nitrate for gunpowder. The cave’s cool temperatures, low humidity, and relatively dry earth floors favored preservation of nitrates, and the surrounding area offered willow for charcoal and nearby lead smelting that produced sulfur as a byproduct. References by Henry Rowe Schoolcraft in 1819 indicate that saltpeter works here predated statehood. The process involved shoveling cave dirt into V-shaped vats, leaching it with water to produce a nitrate-rich mother liquor, passing that liquid through wood ashes to convert calcium nitrate to potassium nitrate, and then boiling it dry to collect saltpeter crystals for shipment or further processing into gunpowder. Around the turn of the 19th century, migrants from Southern Appalachia, where cave-based saltpeter manufacture was common, arrived in the area, and local southerners John Stanton and Steven Sullivan helped revive the works and munitions plants. During shortages in the War of 1812, production here increased, but after statehood local manufacture declined as black powder again became cheaper to obtain and gun technology later advanced. Early in 1861, when the Civil War reached the area, local Southern sympathizers put the cave and munitions ruins back into use, and they remained in Southern hands until Union troops occupied the area in 1862. It is unclear whether Northern troops used the munitions plant or simply let it decline, but it appears more certain that the plant was destroyed when Confederate General Sterling Price’s troops passed through in 1864 during Price’s Raid. The cave kept the name Saltpeter Cave until it was commercialized by Lester B. Dill in 1933, and before then local people used it for dances, picnics, and outings.
