Redgranite Quarry

Redgranite Quarry in Waushara County, Wisconsin, takes its name from the distinctive rock that the quarrying operation extracted from this central Wisconsin site—a granite of reddish coloration that reflects the mineral composition of the Precambrian basement rock exposed by the quarrying operations and now visible in the walls of the flooded pit that has become the dive site. The red granite gives this quarry a geological character distinct from the limestone quarries that dominate diving in the Midwest's southern tier, and the rock's mineral composition contributes to the water chemistry that shapes the clarity and biological community of the flooded pit. Wisconsin's granite quarry diving occupies a niche within the state's freshwater diving landscape—the hard rock of the ancient Precambrian basement creates pit lakes with different clarity and bottom character than the soft limestone quarries of Indiana and Ohio. Redgranite's water, filtered through resistant granite rather than dissolving limestone, maintains a chemical composition that supports good clarity in favorable seasonal conditions, and the rocky walls of the quarry pit create the vertical structural character that distinguishes quarry diving from flat-bottomed lake diving. The quarry's depth profile, shaped by the extraction operations that created it, provides depth variation within the accessible recreational diving range—shallower areas near the quarry walls transitioning to deeper central basin zones that require more gas management than shallow-water training allows. This progression of depth creates a site that accommodates divers at multiple certification levels, allowing beginner and intermediate divers to find appropriate zones while providing deeper water for those pursuing advanced open-water and technical diving skills in a freshwater environment. Freshwater fish have established populations in Redgranite since the quarry filled with groundwater and rain, with bass species being the most commonly encountered dive companions in the structure-rich quarry environment. Largemouth bass—the freshwater fish that seems to colonize every suitable American freshwater environment with the territorial confidence of a species that has optimized for almost every condition—inhabit the quarry's rocky margins with predictable reliability. Crayfish cover available substrate at every depth accessible to recreational divers, their abundance reflecting the productivity of even low-nutrient quarry environments once the biological community has had time to establish. For central Wisconsin divers, Redgranite Quarry provides a local freshwater diving resource within reasonable driving distance of communities in Waushara and surrounding counties that might otherwise require long drives to reach productive dive sites in the Cuyuna Range of Minnesota or the Illinois and Ohio quarry sites that serve the broader Midwest diving community. The quarry's distinctive granite geology and the visual character of its red-tinted walls give it a unique aesthetic among Wisconsin's freshwater dive sites, worth experiencing as part of a systematic exploration of the upper Midwest's diverse freshwater diving resources.