Värnen, also called Trollebosjön, is located in Vetlanda municipality about 20 km southeast of Vetlanda. The lake is part of the Emån water system and is drained via the Farstorpaån (Skärveteån).
The lake surface area is 283 ha and the shoreline is 18.9 km. Värnen is mostly surrounded by forest. It is a shallow lake with an average depth of about 3 m. There are five deep holes where it is more than 5 m deep. The maximum depth is 17 m. The lake is largely shallow and covered with reeds on the shoreline, which makes fishing from land limited.
Rowing boats are available for rent for those who do not have the opportunity to have their own boat in the lake.
Perch and pike are the most common fish species in the lake, but bream, carp, roach, rudd, whitefish and tench are also found.
