Chachoengsao or Paet Rio is located on the east of Bangkok. Its fertility is due to Bang Pakong River. It is an important venue for agricultural products in the Central Region, with mango as the most popular fruit of the province. Moreover, it is the location of the sacred Phra Phutthasothon Buddha image.

Derived from Khmer, the name Chachoengsao means deep canal, while the name of Paet Rio (Paet means eight and Rio means stripes) has been believed to have come from the way dried fish (which are abundant in the area) were being pierced into eight stripes.

The history of Chachoengsao dated back since the Ayutthaya Period during the reign of King Phra Borom Tri Lokkanat. Most people live along the banks of Bang Pakong River and canals. Phra Phutthasothon or Luang Pho Sothon is the center of beliefs and faith. In the past, Chachoengsao was a small town, and was upgraded to a province in 1916.

Chachoengsao is 80 kilometers from Bangkok, with the area of 5,351 square kilometers. The local administration is divided into 10 Amphoe (district) and 1 King Amphoe (sub-district), namely: Amphoe Muang, Bang Khla, Bang Nam Prieo, Bang Pakong, Ban Pho, Phanom Sarakham, Sanam Chai Khet, Plaeng Yao, Ratchasan, Tha Takiap, and King Amphoe Khlong Khuean.