Olonetz, a N. W. government of Russia, bordering on the governments of Archangel, Vologda, Novgorod, and St. Petersburg, and on Lake Ladoga and Finland; area (exclusive of lakes), 50,495 sq. m.; pop. in 1867, 302,490, mostly Russians, Finns, and Lapps. The surface is in great part covered by forests, marshes, and lakes. Of the latter, besides Lake Ladoga on the border, the largest are Lakes Onega and Vyg. The principal rivers are the Onega, which flows through Archangel into Onega bay, an inlet of the White sea; the Svir, which connects Lakes Onega and Ladoga; and the Vodla, which flows from Lake Vodlo into Lake Onega. The winters are very long, and the short summers excessively hot. Agriculture is much neglected; hemp and flax are among the principal articles raised. Fishing and hunting are leading occupations of the inhabitants. Pasturage is scarce, and grazing neglected. Some copper, and iron sufficient to supply ten blast furnaces, are mined, and large quantities of porphyry and marble are quarried.

The principal towns are Petrozavodsk, the capital, on the W. shore of Lake Onega, with about 11,000 inhabitants; Olonetz, the former capital, a small town near the E. shore of Lake Ladoga; Vytegra, on a river of the same name; and Kargopol, on the Onega.