Phra Nakhon Si Ayutthaya is one of the central provinces of Thailand, neighboring provinces (from north clockwise), Ang Thong, Lop Buri, Saraburi, Pathum Thani, Nonthaburi, Nakhon Pathom and Suphan Buri. Ayutthaya name derives from the Ayodhya of the epic Ramayana. At the ruins of the old capital of Ayutthaya historical park are now a UNESCO World Heritage site, and it has been since December 1991. The province is also in the Bang Pa-in summer palace complex. At first the province was named as Krung Kao afterwards it was renamed again to Phra Nakhon Si Ayutthaya.

Phra Nakhon Si Ayutthaya, which covers 2556 square kilometers, is located in a flat valley of the Chao Phraya Valley. The presence in Lop Buri and Pa Sak River to make the province a major rice agriculture. Ayutthaya, one of the biggest tourist attraction, and was founded in 1350 by King U-Thong. It was the capital of Thailand (then called Siam) for 417 years from 1350 until he was sacked by the Burmese army in 1767. In this era of Ayutthaya were 33 kings of different dynasties ruling the kingdom of this period, the Thai history.