Kep (Khmer: ខេត្តកែប, UNGEGN: Kêb, ALA-LC: Kaep [kaep]) is the smallest province (khaet) of Cambodia covering 336 km² (130 sq mi), with a population of 41,798. It is one of the newest Cambodian provinces, together with Pailin, Sihanoukville, and Tboung Khmum, created by Royal Decree on 22 December 2008, which separated Kep Municipality & Damnak Chang’aeur District from the Kampot province, as well as adjusting several provincial borders. It is both the smallest and least populous province of Cambodia. The provincial capital is Kep and the province contains the Kep National Park.

The territory of Kep is entirely surrounded by Kampot province except for the 16 km of sea coast on the southern side fronting the Gulf of Thailand and the Vietnamese island of Phú Quốc. The western limit is 20 km from the town of Kampot. The eastern limit is some 20 km from the Vietnamese border.

It is subdivided into one district and one municipality, further divided into five communes.

• Damnak Chang’aeur: It is the largest of the province and is divided into three quarters – Angkaol to the west, Ou Krasar at the center and Pong Tuek at the east – and 11 groups (Krom). It was the place where Australian David Wilson, 29, Briton Mark Slater, 28, and Frenchman Jean-Michel Braquet, 27, were kidnapped by a Khmer Rouge guerrilla unit led by Commander Chouk Rin in June 1994.
• Kep Municipality: The municipality, located at the center of the province, is subdivided into two quarters Sangkat Kep at the east of the Kep Peninsula and Sangkat Prey Thum at the west, and five groups.

1. Koh Tonsay (កោះទន្សាយ, ‘Rabbit Island’)
2. Koh Kok (កោះកុក, Egret Island)
3. Koh Mtes (កោះម្ទេស, Chili Island)
4. Koh Svay (កោះស្វាយ, ‘Mango Island’)
5. Koh Tbal (កោះត្បាល់, ‘Millstone Island’)
6. Koh Hal Trei.(កោះហាលត្រី, ‘Dry Fish Island’)
7. Koh Svay Prey (កោះស្វាយព្រៃ), ‘Wild Mango Island’)
8. Koh Sarang (កោះសារ៉ាង ‘Sarang Island’)
9. Koh Pou (កោះពោធិ or Pura Island, ‘Enlightening Island’)
10. Koh Makprang. (កោះម៉ាកប្រាង, ‘Makprang Island’ – A Cambodian wild small fruit like a mango.)
11. Koh Angkrong (កោះអង្គ្រង, ‘Angkrong Island’ – Angkrong is the Ziziphus Cambodian tree species.)
12. Koh Ach Seh (កោះអាចម៍សេះ, ‘Horse Dung Island’, however, the name is popular evolving to just Kos Seh – Horse Island.)
13. Koh Snguot. (កោះស្ងួត, ‘Dry Island’)

Koh Tonsay (Khmer: កោះទន្សាយ meaning ‘Rabbit Island’) is located about 4.5 Kilometers southwest of Kep. Tourists are drawn to the two white sand beaches, and the sea is shallow and proper for swimming. At the sea bottom are a variety of corals, sea animals, and plants which attract researchers and ecologists.

The name Koh Tonsay is derived from the word Rumsay. While trying to avoid the commander’s troops, Prince Sakor Reach grew hopeless because his troops began to tire. He led his remaining troops across the sea to an island in front of Kep city, where the troops spread out. Accordingly, the island was called Koh Rumsay, Koh Ormsay, Koh Ornsay, and Koh Tonsay, as it is known today. Another version is that, according to many locals who spent their youth in Kep before 1975, the island was previously called Koh Antai. There is no apparent meaning for this word.

Koh Tonsay is 2 square kilometers in area. During then-Prince Norodom Sihanouk’s Sangku Reastr Niyum regime, it was used as a place to rehabilitate criminals, who were also used to defend the island. Horse cart paths and wooden, thatch-roofed motels were also constructed during this time. Most of this infrastructure has been destroyed by weather and decades of war. Today Koh Tonsay is a major tourist attraction for Kep. There are about 8 Khmer-run basic guest houses and about 5 restaurants, serving mainly fresh seafood like crabs, shrimp, and fish. During the day it can get quite busy with day tourists, who leave around 4 pm, so for the sunset, there are only a few overnight people there. Electricity runs only from 6-9 pm by generators. Water can run short during the dry months (Dec-Apr), Long-tail boats with big water tanks supply the island with water.

Under French rule Kep belonged to the Circonscription Résidentielle de Kampot, developing into Cambodia’s most prestigious beach town. Established as such in 1908 and named Kep-sur-Mer it was a thriving resort town for the French and Cambodian elite until the early 1970s,

Constructed between 1953 and 1970 – after French occupation, Kep’s modernist villas are unique. Architects Vann Molyvann and Lu Ban Hap who embodied Cambodia’s golden age of architectural modernism, blended elements of the modern movement (Bauhaus, Richard Neutra and Le Corbusier) with traditional Khmer architecture, promoted by King Sihanouk – known as New Khmer Architecture.

A major misconception about Kep is that during the Khmer Rouge years, much of Kep’s French colonial era mansions and villas were destroyed. In fact, local residents, being in need of money and food, stripped down the villas so that they could exchange all these valuable parts in Vietnam for rice and cash.^{[citation needed]} Many of Kep’s villas are abandoned, but some of the town’s former splendor is still apparent.

The ocean is lined with wide sidewalks and large statues. Prince Norodom Sihanouk not only kept his own villa, but his own island as well. Ile des Ambassadeurs was a favorite spot for Sihanouk to entertain a regular stream of guests.

A paved road connects the town with Kampot. Kep’s coastline consists mostly of mangrove marshes and black rock rather than the white sands of Sihanoukville, although a beach nourishment with the white sand of Sihanoukville has made the beach wider and cleaner.

There are now more than 60 guesthouses, resorts and hotels in Kep. It is currently one of the fastest developing touristic areas in Cambodia with a focus on mid-range to high-end businesses.