Greyhawk Wiki Entry on Lake Quag

Lake Quag is the third largest body of fresh water in the Flanaess. Fish are plentiful in its waters, including giant pike and gar and is a source of considerable wealth and food for Perrenland, although the fishers themselves are sometimes eaten. The waters are far from safe, especially in the colder months.

Nixies are also known to dwell beneath the waters of the lake, effectively ruling most of the western depths. These fey are shy and reclusive but have a good relationship with the druids of Perrenland. Lizardfolk also dwell on the shorelines in various places. These creatures are generally peaceful as they follower the Old Kerk and nature as a whole.

While Perrenland controls most of the coast and the majority of the water, the northern shore is controlled by the Tiger Nomads and Wolf Nomads. The town of Ungra Balan is the only major settlement on the shoreline, although the lesser towns of Wallport, Zuis and Greypike also hug the shoreline to the east of Ungra Balan. These are technically within Wolf Nomad territory.

Considerable traffic is on the lake for most of the year, including Rhennee bargefolk in the summer, though the surface often freezes in midwinter. Special sled-like boats called iceskimmers sometimes sail on the lake at these times, though it is dangerous to take them far from shore.

The very center of the lake is something of an enigma and countless ships have disappeared forever in the grey fogs. Undead have been seen in this region, possibly guarding some hidden treasure or location, but no one can say for sure. Most who travel here are never seen again but others are discovered haunting the waters as undead in terrible ghostly vessels. Fortunately, these ghost ships do not stray far from the place where their crew was slain.

The Velverdyva River drains Lake Quag before heading south. The Fler is the principle inlet to Lake Quag, water draining from the Land of Black Ice in the far north.