21 provinces (aimags in Mongolian), the capital city (Ulaanbaatar), including 3 autonomous cities (Darkhan, Erdenet and Choir). The provinces are subdivided into sums, or district of which there are 298. The biggest province is South Gobi Province (Umnugobi aimag) which occupies an area of 165,000sq.km but due to its rigorous climatic conditions has the smallest population (only 42,400 people).