Cambodia is divided into 25 provinces (Khmer: ខេត្ត, khaet, singular and plural). The capital Phnom Penh is not province but a special administrative area and is included as the 25th province since it is administered at the same level as the other 24 provinces. The name of the provinces are the same as that of their respective capital cities, except for Banteay Meanchey, Kandal, Mondulkiri, Oddar Meanchey, Rattanakiri, Koh Kong, Kampong Thom, Takeo, Kampong Speu, and Tboung Khmum.
Phnom Penh has both the highest population and the highest population density. The largest province by area is Mondulkiri and the smallest Phnom Penh. Kep has the lowest population, while Mondulkiri has the lowest population density (facts according to the year 2000 census).
Each province is administered by a governor, who is appointed by the Ministry of Interior.
Cambodia is subdivided into 159 districts (srok, ស្រុក). The nine districts of Phnom Penh are called khan (ខណ្ឌ), but even in official documents they are sometimes misidentified as srok. The number of districts in each provinces varies, from two in the smallest provinces to 13 in Battambang, Prey Veng, and Siem Reap. Further subdivision levels are khum (subdistricts), sangkat (quarters) and finally, phum (villages). In Phnom Penh there are no khum.
In 1975 the Khmer Rouge government did away with all former Cambodian traditional administrative divisions. Instead of provinces, "Democratic Kampuchea" was divided into seven geographic zones: The Northwest, the North, the Northeast, the East, the Southwest, the West and the Center.
These zones were derived from divisions established by the Khmer Rouge when they fought against the Khmer Republic led by general Lon Nol.
On 22 December 2008, King Norodom Sihamoni signed a Royal Decree that changed the municipalities of Kep, Pailin and Sihanoukville into provincial municipalities, as well as adjusting several provincial borders.