Bala Lake (Welsh: Llyn Tegid) is in Gwynedd, North Wales. It is the largest natural body of water in Wales, at 4 miles (6.3 km) long by 1 mile (1.6 km) wide with a maximum depth of 42 meters.
In Welsh the lake is known as Llyn Tegid, meaning Lake of Serenity. Local legend states that the lake is inhabited by a monster known as “Teggie”. It is subject to sudden and dangerous floods. The River Dee runs through it and the waters of the lake are famously deep and clear. The town of Bala sits at its northern end.