Bristol Bay (Iilgayaq in Central Yup'ik) is the eastern-most arm of the Bering Sea, at 57° to 59° North 157° to 162° West. It is located between the southwest part of the Alaska mainland to its north, and the Alaska Peninsula to its south and east. Bristol Bay is 400 km (250 miles) long and 290 km, (180 miles) wide at its mouth. A number of rivers flow into the bay, including the Cinder, Igushik, Kvichak, Meshik, Nushagak, Naknek, Togiak, and Ugashik.
Upper reaches of Bristol Bay experience some of the highest tides in the world. One such reach, the Nushagak Bay near Dillingham and another near Naknek in Kvichak Bay have tidal extremes in excess of 30 feet (9.9 m), ranking them — and the area — as eighth highest in the world. This, coupled with the extreme number of shoals, sandbars and shallows, makes navigation troublesome, especially during the area's frequently strong winds.
As the shallowest part of the Bering Sea, Bristol Bay is understandably one of the most dangerous areas for large vessels. This is one reason why the Bristol Bay commercial salmon fishing fleet is limited to 32-foot (10 m) overall keel length. In addition, most of the area is not well documented by nautical charts and navigational aids are sparse.
