Chuvashia  The Chuvash Republic (, "Chuváshskaya Respúblika — Chuváshiya"; , "Čăvaš Respubliki"), or Chuvashia ( "Chuváshiya"; , "Čăvaš Jen"), is a federal subject of Russia (a republic). It is the homeland of the Chuvash people, a Turkic ethnic group. Its capital is the city of Cheboksary. As of the 2010 Census, its population was 1,251,619. The Chuvash Republic is located in the center of European Russia, in the heart of the Volga-Vyatka economic region, mostly to the west of the Volga River, in the Volga Upland. It borders with the Mari El Republic in the north, Nizhny Novgorod Oblast in the west, the Republic of Mordovia in the southwest, Ulyanovsk Oblast in the south, and the Republic of Tatarstan in the east and southeast. There are over two thousand rivers in the republic—with the major ones being the Volga, the Sura, and the Tsivil—as well as four hundred lakes. Some of the Volga River valley reservoirs are in the north of the republic, and the Sura River flows towards the Volga along much of the republic's western boundary. Climate is moderate continental, with the average temperatures ranging from in January to in July. Annual precipitation varies between , but is uneven from one year to another. Natural resources include gypsum, sand, clay, sapropel deposits, phosphorite, and peat. There are oil and natural gas deposits, although their extraction has not yet been commercially pursued. Forests, mostly in the south along the Sura River, cover approximately 30% of the land. The ancestors of the Chuvash were Bulgars and Suars, Turkic tribes residing in the Northern Caucasus in the 5th to 8th centuries. In the 7th and 8th centuries, a part of the Bulgars left for the Balkans, where, together with local Slavs, they established the state of modern Bulgaria. Another part moved to the Middle Volga Region (see Volga Bulgaria), where the Bulgar population that did not adopt Islam formed the foundation of the Chuvash people. During the Mongol invasion of Volga Bulgaria, the steppe-dwelling Suar migrated north, where Volga Finnic tribes, such as the Mordvins and Mari lived.