At the border of three counties is Lake Võrtsjärv, the largest inland water body (270 km ²) in Estonia. The bottom of the lake is gradually shallow and in the summer, the water temperature is often above 20 degrees. In Lake Võrtsjärv there are over 30 species of fish, including pike and eel; the lake is the largest eel farming site in Estonia. The glass eels carried with the currents of the Atlantic Ocean from the Sargasso Sea to the coast of England have made a huge air journey and continue their lives in the water of Lake Võrtsjärv.
On the east coast of the lake is the Center of Limnology of Lake Võrtsjärv. In the rest area of Rannu-Jõesuu, a building made of ecological materials (wood, chipboard, clay and straw) - Lake Võrtsjärv Visitor Center – has been built for tourists. Here one can get information on recreation and accommodation facilities near the lake, as well as to order trawler yacht rides on Lake Võrtsjärv and buy souvenirs made by local artisans. Not far from the visitor center is a 15 m high watch tower. Around the lake is a marked 140 km long bicycle lane.