The district office is at Kolar. It is the easternmost district of the state, situated in southern Karnataka. The district is bordered on the west by the Bangalore Rural district, on the north by the Chikballapur district, on the east by the Andhra Pradesh districts of Chittoor and Annamayya, and on the south by the Tamil Nadu district of Krishnagiri.

It split on September 10, 2007, to become the new district of Chikballapur. The district is now referred to as India’s “Golden Land” because of the discovery of the Kolar Gold Fields.