Tumkur District ( ತುಮಕೂರು ಜಿಲ್ಲೆ) is an Administrative district in the state of Karnataka in India. The district headquarters are located at Tumkur. The district occupies an area of 10,598 km² and had a population of 2,584,711, of which 19.62% were urban as of 2001. It is a one and a half hour drive from Bangalore, the capital of Karnataka.
It consists chiefly of elevated land intersected by river valleys. A range of hills rising to nearly 4,000 feet (1,200 m) crosses it from north to south, forming the watershed between the systems of the Krishna and the Kaveri. The principal streams are the Jayamangala and the Shimsha. The mineral wealth of Tumkur is considerable; iron is obtained in large quantities from the hillsides; and excellent building-stone is quarried. The slopes of the Devarayanadurga hills are clothed with forests. Wildlife such as leopards, bears and wild boar have been recorded here. Although, tigers have been recorded from these forests as late as 1950s, most recent reports are of stray sightings and need confirmation. The annual rainfall averages 39 inches
Tumkur consists of 10 Taluks namely Chikkanayakanahalli, Sira, Tiptur, Tumkur, Turuvekere, Kunigal, Gubbi, Madhugiri, Koratagere and Pavagada.
Tumkur is a good study center from primary education to higher education. It has its own university. Within this town, there are four technology institutions and one medical institution.