Sihanoukville (Khmer: ក្រុងព្រះសីហនុ - Krong Preah Sihanouk), also known as Kampong Saom, is a province (khaet) of Cambodia on the Gulf of Thailand. This port city is a growing Cambodian urban center, located 185 kilometres (115 mi) southwest of the Cambodian capital, Phnom Penh. The province is named after King Father Norodom Sihanouk and grew up around the construction of Sihanoukville Port. Construction on the port began in June 1955 and it was the only deep water port in Cambodia.^[2] The port was built in part due to the waning power of the French leading to the Vietnamese tightening their control over the Mekong Delta and hence restricting river access to Cambodia. Sihanoukville's beaches have made it a popular tourist destination.^[3]

The province is served by Sihanoukville International Airport, 18 kilometres (11 mi) from downtown, although it has a limited commercial operation. The planned flights between Sihanoukville and Siem Reap may encourage visitors to Angkor temples in Siem Reap to extend their stay, though the crash of a charter flight in Phnom Damrey on 25 June 2007 from Siem Riep,^[4] has caused concerns. The flights are scheduled to start on December 14, 2011.

Sihanoukville attracts tourists with its relaxed beach atmosphere when compared to Thailand's more developed ones. However, the city has attracted not only tourists, but several NGOs and foreign and national investors in the last years in order to develop not only the growing tourist industry, but its capacity as an international sea port^[5] and other sectors like textile and real estate.^[6] In Sihanoukville is also located the main factory of Angkor Beer, the Cambodian national beer.

Sihanoukville was the place of the last official battle of the United States army in the Vietnam War, although the incident took place outside Vietnam. It is known as the Mayagüez incident on May 12–15, 1975 between the US forces and the Khmer Rouge. Currently, visitors dive in Koh Tang, one of the Sihanoukville islands where the major battle to free the SS Mayagüez took place. Divers can see two shipwrecks 40 metres (130 ft) down.^[7]

On 22 December 2008, King Norodom Sihamoni signed a Royal Decree that changed the municipalities of Kep, Pailin and Sihanoukville into provinces, as well as adjusting several provincial borders

The province honors the name of King Norodom Sihanouk. Internationally it is written in French as Sihanouk Ville or Sihanoukville (Literally "The City of Sihanouk" or "Sihanouk City").

King Norodom Sihanouk is known in Cambodia as the Father of the Nation,^[9] because he was the main promoter of the independence of the country from France in 1953.

The name "Sihanouk" is formed from two Sanskrit words: Siha and Hanu. "Siha" means Lion. The word comes from Sanskrit "Simha". Another example is Singapore. "Hanouk" is from "Hanu" that means "Jaws". Therefore, Sihanouk is "The Jaws of the Lion".

The former name Kompong Saom means "Agreeable Port" and som is derived from the Sanskrit word "samuya

As the newest Cambodian city, Sihanoukville doesn't have a long history like Phnom Penh or Siem Reap. It was founded in 1960 after independence from France as a port, in order to communicate the city with international trade. The project was overseen by the government of Norodom Sihanouk.

The construction of the port began in 1955 and most of the families of the builders remained near the port, effectively becoming the first inhabitants.

During the Vietnam War, it became an intensive military port first in the service of National Front for the Liberation of South Vietnam and after 1970, with the regime of General Lon Nol, at the service of the United States.

With the success of the Khmer Rouge guerrillas in April 1975, the port was the last place to be evacuated by the US army. The SS Mayagüez was captured by militants of the new regime on 12 May. The US claimed that the ship was on international sea lanes, but the Khmer Rouge said that it was on Cambodian territory. It is known as the Mayagüez incident.

After the fall of the Khmer Rouge regime in 1979, the port of Sihanoukville recovered a great importance in the development of the country. With the opening of markets in 1999, the port became one of the main spots of economical growing of Cambodia.

In December 1999, Formosa Plastics bribed^[10] Cambodian officials and dumped 3000 tons of mercury laden waste into Sihanoukville, killing 3 people. Formosa Plastics also tried to dump the waste in the Nevada, USA.^[11]