From the Wikipedia page 
Kostroma Oblast (Russian: Костромска́я о́бласть, Kostromskaya oblast) is a federal subject of Russia (an oblast). Its administrative center is the city of Kostroma. It was formed in 1944 on the territory detached from neighboring Yaroslavl Oblast.
Kostroma Oblast borders Vologda Oblast (N), Kirov Oblast (E), Nizhny Novgorod Oblast (S), Ivanovo Oblast (S), and Yaroslavl Oblast (W). The main rivers are the Volga and the Kostroma. Much of the area is covered by woods, making it one of the principal timber producing regions in Europe.