ONEGA, Gulf of, the south-western arm of the White Sea, runs into the land in a S.E. direction, having a length of 75 miles, and a breadth at its mouth of 60 miles. It receives at its head the River Onega, which issues from Lake Latcha in Olonetz, flows N.E. to the confines of Archangel, and thence N.W. to the sea; total length, 270 miles. It is used for floating down timber, but is seldom navigated on account of the numerous falls and rapids.