Chai Nat (Thai: ชัยนาท, pronounced [tɕʰāj nâːt]) is one of the central provinces (changwat) of Thailand. Neighbouring provinces are (from north clockwise) Nakhon Sawan, Sing Buri, Suphan Buri, and Uthai Thani. The town of Chai Nat is 188 km north of Bangkok.
According to the Ayutthaya Testimonies, the provincial center of Chai Nat was founded by the Siamese monarch Surindrarāja in the early 11th century. He renamed Ban Pran Nuea (บ้านพรานเนื้อ) as Phra Nakhon Chai Nat Buri (พระนครชัยนาทบุรี) and designated it as the new capital of the region, thereby superseding Phraek Si Racha as the principal administrative center of the polity.