ChaiNat (Thai ชัยนาท) is one of the central provinces (jangwat) of Thailand.
ChaiNat is located in the flat river plain of central Thailand's Chao Phraya River valley.
In the south of the province the Chao Phraya (formerly ChaiNat) Dam impounds the Chao Phraya river, both for flood control as well as to divert water into the country's largest irrigation system for the irrigation of rice paddies in the lower river valley.
ChaiNat is located on the east bank of the Chao Phraya River.
ChaiNat was an important town used several times as a base to confront the Burmese army.
ChaiNat occupies an area of 2,469 square kilometres and is administratively divided into 6 districts and one sub-districts: Amphoe Muang ChaiNat, Amphoe Hankha, Amphoe Manorom, Amphoe Sankhaburi, Amphoe Sapphaya, Amphoe Wat Sing and King Amphoe Nong Mamong.