Prachuap Khiri Khan (Thai ประจวบคีรีขันธ์) is one of the central provinces (changwat) of Thailand. To the west it borders Tanintharyi Division of Myanmar.

The district is located on the Kra Isthmus, the narrow landbridge connecting the Malay Peninsula with mainland Asia. The province contains the narrowest part of Thailand - directly south of the capital it is just 13 kilometers from the coast of the Gulf of Thailand to the border with Myanmar. The narrowest point of the Isthmus is however further south in the province Chumphon.Physiographically Prachuap Khiri Khan is moderately plain area with altitude varying from 0 - 1200 meters above MSL. The maximum altitude can be reached in the north eastern and central west regions, which makes approximately 30% of the area.

The long coast to the Gulf of Thailand has many sandy beaches, the most famous one being at Hua Hin, which has been a popular resort since King Prajadhipok (Rama VII) built a summer palace there. From the coast the land quickly rises into the mountain chain which forms the border to Myanmar, the highest elevation in the province being the 1494-meter-high Khao Luang. Due to this narrow watershed the rivers in the province are all small, the only bigger one is the Pran Buri River in the north of the province.

The Khao Sam Roi Yot National Park was established in 1966 to protect Thailand's largest freshwater marshes, but also contains some mangrove woods and mudflats. Most of the marshes were converted into shrimp farms, despite being in a national park.

The city of Prachuap Khiri Khan was reconstructed in 1845, after it was abandoned during the fall of the Ayutthaya kingdom in 1767.

King Mongkut gathered 3 cities, Bang Nangrom, Kui Buri and Khlong Wan to sattle and name Prachuap Khiri Khan province. At the same time, he renamed Koh Kong,the opposite city that located in the east side of Gulf of Siam(recently Gulf of Thailand) to be Prachanta Khiri Khet. Now Koh Kong is a province of Kingdom of Cambodia.

In 1868 King Mongkut invited several guests to watch the solar eclipse on September 18. Being fond of science he predicted the event by himself, but the chosen observation point was the marshes near Sam Roi Yot where he contracted malaria, of which he died two weeks later.

During World War II Japanese troops occupied Thailand. On December 8, 1941 they first landed near the city of Prachuap Khiri Khan. After one day of battle the Thai troops resigned and had to allow Japan to use Thailand as a base for their war operations.

The provincial seal show the Kuha Karuhas pavilion, which was built when King Chulalongkorn (Rama V) visited the Praya Nakorn Cave (King Amphoe Sam Roi Yot). Depicted behind the pavilion is the island of Ko Lak in Prachuap bay, the historic center of administration.

The provincial tree as well as the provincial flower is the rayan or manilkara (Manilkara hexandra).

The province is subdivided into 8 districts (Amphoe). The districts are further subdivided into 48 communes (tambon) and 388 villages (muban).

Extracted from Wikipedia: Prachuap Khiri Khan Province