Lake Tarnowskie Wielkie, located in the Sławskie Lakeland within the Wschowa County, is a body of water with a surface area ranging from 91.6 to 97.5 hectares and an average depth of 3.8 meters. It is surrounded by a diverse landscape, featuring both cliff-like shores and flat terrains, making it attractive to both anglers and leisure seekers. The lake has been known since 1802 under various names, with its current name officially adopted in 1954. The lake's waters are primarily fed by atmospheric precipitation and groundwater, with outflow occurring through the Cienica stream into Lake Sławskie. The region around the lake holds significant recreational value; it once hosted four holiday resorts and a campsite. In recent years, despite some water quality issues, the lake has maintained a moderate ecological status. The local fauna includes numerous species of fish and birds, making the area important both ecologically and culturally. The lake is also part of a protected landscape area and the Natura 2000 network, underscoring its significance for biodiversity conservation. Over the years, various factors, such as its relatively shallow average depth and varying water temperatures, have influenced the dynamic state of the lake's ecosystem, making it an interesting subject for research and a designated area for environmental protection.