Kastornoye is an urban locality located in the Kursk Oblast of Russia. It serves as the administrative center of the Kastorensky District.
According to census data, the population of the city has fluctuated over recent decades. The 2021 census recorded a population of 3,461 residents, following figures of 3,848 in 2010 and 4,492 in 2002. The town is identified by the telephone code +7 47157 and the postal code 306700.