ToponymyThe word ''nakhon'' originates from the Sanskrit word ''nagara'' (Devanāgarī, Devanagari: नगर) meaning 'city', and the word ''nayok'' is thought to have been derived from the Sanskrit ''nāyaka'' (Devanāgarī, Devanagari: नायक) meaning 'leader' or 'captain'. However, in this connection, ''na'' means '[tax of] rice field' and ''yok'' means 'exempted'. Hence the name of the province literally means 'tax-free city'.
HistoryThe city of Nakhon Nayok dates back to the Dvaravati Kingdom, probably founded in the 11th century. Ruins from this time are visible at Mueang Boran Dong Lakhon south of the modern city. Originally named ''Mueang'' Lablae, the name "Nakhon Nayok" was assigned to it in 1350, when it became a garrison town of the Ayutthaya kingdom protecting the eastern boundary. On 1 January 1943 the government downgraded Nakhon Nayok Province and combined it with Prachinburi Province, except for Ban Na District which became part of Saraburi Province. On 9 May 1946 the province was re-established.
SymbolsThe Seals of The Provinces of Thailand, provincial seal shows an elephant holding an ear of rice with its trunk. This symbolizes fertile rice fields, as well as the forests with numerous elephants. In the background two piles of straw, trees, and clouds symbolizing the natural beauty of the province. The provincial flower and tree is the silk cotton tree (''Cochlospermum religiosum'').
ClimateNakhon Nayok province has a tropical savanna climate (Köppen climate classification category Aw). Winters are dry and warm. Temperatures rise until May. Monsoon season runs from May through October, with heavy rain and somewhat cooler temperatures during the day, although nights remain warm. Climate statistics: maximum temperature is 42.2 °C (108 °F) in April and lowest temperature is 12.2 °C (54 °F) in December. Highest average temperature is 36.8 °C (98.2 °F) in April and minimum average temperature is 20.5 °C (68.9 °F) in December. Average annual rainfall is 1,823 millimeters in 134 days. Maximum daily rainfall is 195 millimeters in August.
GeographyThe northern part of the province is in the Sankamphaeng Range, the southern prolongation of the Dong Phaya Yen mountains, with the highest elevation the 1,292-meter-high Yod Khao Kiew. Most of that area is covered by the Khao Yai National Park. The total forest area is or 30 percent of provincial area. The central part of the province however is a rather flat river plain formed by the Nakhon Nayok River. The southern part of the province has relatively infertile acidic soil. The main river of the province is the Nakhon Nayok River. It joins the Prachinburi River at Pak Nam Yothaka in Ban Sang District, Prachinburi Province, which then becomes the Bang Pa Kong River.
Administrative divisionsImage:Amphoe Nakhon Nayok.svg, Four districts of Nakhon Nayok
Provincial governmentThe province is divided into four districts (''amphoes''). The districts are further divided into 41 subdistricts (''tambons'') and 403 villages (''mubans''). #Mueang Nakhon Nayok District, Mueang Nakhon Nayok #Pak Phli District, Pak Phli #Ban Na District, Ban Na #Ongkharak District, Ongkharak
Local governmentAs of 26 November 2019 there are: one Nakhon Nayok Provincial Administration Organisation (') and 6 municipal (''thesaban'') areas in the province. Nakhon Nayok has town (''thesaban mueang'') status. Further 5 subdistrict municipalities (''thesaban tambon''). The non-municipal areas are administered by 39 Subdistrict Administrative Organisations - SAO (''ongkan borihan suan tambon'').
Human achievement index 2017Since 2003, United Nations Development Programme (UNDP) in Thailand has tracked progress on human development at sub-national level using the Human achievement index (HAI), a composite index covering all the eight key areas of human development. National Economic and Social Development Board (NESDB) has taken over this task since 2017.
NotesReports (data) from Thai government are "not copyrightable" (Public Domain), Copyright Act 2537 (1994), section 7.