The main river of the region is the Dnieper River and its tributaries, Desna, Vop, Vyazma. By the rivers of the Volga basin and its tributary Vazuza Gzhat and tributary of the Oka river, Ugra. To the north-west flows a short section of the Western Dvina River and its tributary river Kasplya .
Among the major reservoirs supplying water are Moscow Vazuzssky Yauza and reservoirs in the north-east, as well as cooling power plants, Smolensk reservoir in the north near the village of Lake and Desnogorsk Reservoir in the south area of the city near the Desnogorsk.
The climate of Smolensk Oblast is humid continental, similar to the climate of Moscow Oblast, but slightly warmer in winter due to being located further west. Summers are short, warm and rainy, while winters are long, cold and snowy. Average temperatures range from −9 °C (16 °F) in January to 17 °C (63 °F) in July (although in the south it ranges from −8 °C (18 °F) in January to 18 °C (64 °F) in July). Annual precipitation varies from 630 to 730 mm (25 to 29 in) per year.
During the Soviet period, the high authority in the oblast was shared between three persons: The first secretary of the Smolensk CPSU Committee (who in reality had the biggest authority), the chairman of the oblast Soviet (legislative power), and the Chairman of the oblast Executive Committee (executive power). Since 1991, CPSU lost all the power, and the head of the Oblast administration, and eventually the governor was appointed/elected alongside elected regional parliament.
The Charter of Smolensk Oblast is the fundamental law of the region. The Legislative Assembly of Smolensk is the province's standing legislative (representative) body. The Legislative Assembly exercises its authority by passing laws, resolutions, and other legal acts and by supervising the implementation and observance of the laws and other legal acts passed by it. The highest executive body is the Oblast Government, which includes territorial executive bodies such as district administrations, committees, and commissions that facilitate development and run the day to day matters of the province. The Oblast administration supports the activities of the Governor who is the highest official and acts as guarantor of the observance of the oblast Charter in accordance with the Constitution of Russia.
From July 1941-September 1943 part of region fell to Germany.
41,457 people were registered from administrative databases, and could not declare an ethnicity. It is estimated that the proportion of ethnicities in this group is the same as that of the declared group.[22]
Smolensk Oblast has a diverse economy, and exports large amounts of ammonium nitrate, fertilizers, wheat, and wood. The top exports in 2021 were fertilizers (19.2%, $284M), wood products (13.2%, $194M), wheat (9.8%, $144M), and machinery (7.6%, $112M).
^Президент Российской Федерации. Указ №849 от 13 мая 2000 г. «О полномочном представителе Президента Российской Федерации в федеральном округе». Вступил в силу 13 мая 2000 г. Опубликован: "Собрание законодательства РФ", No. 20, ст. 2112, 15 мая 2000 г. (President of the Russian Federation. Decree #849 of May 13, 2000 On the Plenipotentiary Representative of the President of the Russian Federation in a Federal District. Effective as of May 13, 2000.).
^Госстандарт Российской Федерации. №ОК 024-95 27 декабря 1995 г. «Общероссийский классификатор экономических регионов. 2. Экономические районы», в ред. Изменения №5/2001 ОКЭР. (Gosstandart of the Russian Federation. #OK 024-95 December 27, 1995 Russian Classification of Economic Regions. 2. Economic Regions, as amended by the Amendment #5/2001 OKER. ).
^"Об исчислении времени". Официальный интернет-портал правовой информации (in Russian). June 3, 2011. Retrieved January 19, 2019.
^Official throughout the Russian Federation according to Article 68.1 of the Constitution of Russia.
^ abИсполнительный комитет Смоленского областного совета народных депутатов. Государственный архив Смоленской области. "Административно-территориальное устройство Смоленской области. Справочник", изд. "Московский рабочий", Москва 1981. Стр. 8
Смоленская областная Дума. Областной закон №37-з от 15 мая 2001 г. «Устав Смоленской области», в ред. Областного закона №162-з от 26 ноября 2015 г. «О поправке к уставу Смоленской области». Вступил в силу со дня официального опубликования. Опубликован: "Рабочий путь", №116–117, 24 мая 2001 г. (Smolensk Oblast Duma. Oblast Law #37-z of May 15, 2001 Charter of Smolensk Oblast, as amended by the Oblast Law #162-z of November 26, 2015 On the Amendment to the Charter of Smolensk Oblast. Effective as of the day of the official publication.).