Nakhon If Thammarat is one of the southern provinces (changwat) of Thailand, in the oriental coast of the Gulf of Thailand.  The neighboring provinces are (southern to the right) Songkhla, Phatthalung, Trang, Krabi and Gentlemen of Surat. 

The name of the province drifts of its name Pali-Sanskrit Nagara Sri Dhammaraja (the City of the Sacred King of Dharma), that in becames Thai of pronunciation Nakhon If Thammarat. 

The province is located in the coast of the Gulf of Thailand in the zone of the east of the Malayan Peninsula.  The land is mountainous area in its greater rough part of forest.  It contains the highest elevation of Thailand southern, the Khao Luang with 1.835 M, now protected in the Khao Luang the national park. 

The area around Nakhon If Thammarat was the part (according to some scholars still the center) of the kingdom of Srivijaya of the century III to king Ramkhamhaeng of Sukhothai occupied it and added it to its kingdom.  With the fall of Sukhothai that fell it its successor, the kingdom of Ayutthaya.  Nakhon came be a province in 1932.