Kyustendil Province is a province in southwestern Bulgaria, extending over an area of 3,084.3 km², and with a population of 107,673. It borders the provinces of Sofia, Pernik, and Blagoevgrad; to the west, its limits coincide with the state borders between Bulgaria and North Macedonia, and between Bulgaria and the Republic of Serbia. The administrative cent…Kyustendil Province is a province in southwestern Bulgaria, extending over an area of 3,084.3 km², and with a population of 107,673. It borders the provinces of Sofia, Pernik, and Blagoevgrad; to the west, its limits coincide with the state borders between Bulgaria and North Macedonia, and between Bulgaria and the Republic of Serbia. The administrative center of the Province is Kyustendil.