Soviet-era sources (Great Soviet Encyclopedia and others)Сибирь — Большая советская энциклопедия (The Great Soviet Encyclopedia, in Russian) and modern Russian onesСибирь- Словарь современных географических названий (in Russian) usually define Siberia as a region extending eastward from the Ural Mountains to the watershed between Pacific and Arctic drainage basins, and southward from the Arctic Ocean to the hills of north-central Kazakhstan and the national borders of both Mongolia and China. By this definition, Siberia includes the federal subjects of the Siberian Federal District, and some of the Ural Federal District, as well as Sakha (Yakutia) Republic, which is a part of the Far Eastern Federal District. Geographically, this definition includes subdivisions of several other subjects of Urals and Far Eastern federal districts, but they are not included administratively. This definition excludes Sverdlovsk Oblast and Chelyabinsk Oblast, both of which are included in some wider definitions of Siberia.
Soviet-era sources (Great Soviet Encyclopedia and others)Сибирь — Большая советская энциклопедия (The Great Soviet Encyclopedia, in Russian) and modern Russian onesСибирь- Словарь современных географических названий (in Russian) usually define Siberia as a region extending eastward from the Ural Mountains to the watershed between Pacific and Arctic drainage basins, and southward from the Arctic Ocean to the h,ills of north-central Kazakhstan and the national borders of both Mongolia and China. By this definition, Siberia includes the federal subjects of the Siberian Federal District and some of the Ural Federal District, as well as Sakha (Yakutia) Republic, which is a part of the Far Eastern Federal District. Geographically, this definition includes subdivisions of several other subjects of Urals and Far Eastern federal districts, but they are not included administratively. This definition excludes Sverdlovsk Oblast and Chelyabinsk Oblast, both of which are included in some wider definitions of Siberia.