Kaluga Oblast (Калу́жская о́бласть, Kaluzhskaya oblast) is a federal subject of Russia (an oblast). Its administrative center is the city of Kaluga. The 2010 Russian Census found a population of 1,010,930.
Kaluga Oblast lies in the central part of the East European Plain. The oblast's territory is located between the Central Russian Upland (with and average elevation of above 200 m and a maximum elevation of 275 m in the southeast), the Smolensk–Moscow Upland and the Dnieper–Desna watershed. Most of the oblast is occupied by plains, fields and forests with diverse flora and fauna. The administrative center is located on the Baryatino-Sukhinichy plain. The western part of the oblast — located within the drift plain — is dominated by the Spas-Demensk ridge. To the south is an outwash plain that is part of the Bryansk-Zhizdra woodlands, with average elevation up to 200 m.
From north to south, Kaluga Oblast extends for more than 220 km, from 53°30′ to 55°30′ northern altitude, and east to west – for 220 km. Its area is 29,800 km².
The oblast's territory is crossed by major international motor and railways, linking Kaluga with Moscow, Bryansk, Kyiv, Lviv and Warsaw.
Kaluga Oblast borders on:
* Bryansk Oblast to the south-west
* Oryol Oblast to the south
* Tula Oblast to the east
* Moscow Oblast to the north-east
* Smolensk Oblast to the north-west