|Pop. density:||118 inh./km²|
Chachoengsao (Thai ฉะเชิงเทรา) is a province (changwat) of Thailand. Neighboring provinces are (from north clockwise) Prachinburi, Srakaeo, Chanthaburi, Chonburi, Samut Prakan, Bangkok, Pathumthani and Nakhon Nayok . It also has a short coast to the Gulf of Thailand.
The west part of the province is the low river plain of the Bang Pa Kong river, which is used extensively for farming rice. To the east is more hilly terrain, with an average height of more then 100 m above sea level.
The provincial seal shows the main hall of the Sothornvararamvoraviharn temple. In this hall is the most important Buddha image of the province, called Luang Por Buddha Sothorn.
Provincial tree is Peltophorum dasyrachis. The tree has been assigned to the province by Queen Sirikit on the 50th anniversary of the coronation of King Rama IX in 2000. Provincial flower is the Yellow Flamboyant (Peltophorum pterocarpum).