Chao Phraya River แม่น้ำเจ้าพระยา is the main river through Bangkok, Thailand. It is also the main waterway through the kingdom. It starts at the confluence of the Ping and Nan rivers at Nakhon Sawan, and empties into the Gulf of Thailand, over a distance of 372 km (231 miles).
At Chainat, the Chao Phraya River forks into two, with the main river continuing to Bangkok while the smaller Tha Chin River flowing parallel to the Chao Phraya before emptying into the Gulf of Thailand in Samut Sakhon, 35 km (22 miles) to the west of Bangkok.
The area in central Thailand through which the Chao Phraya River flows through is the most densely populated in the country. Apart from Bangkok, which has a population exceeding 9 million people, the other cities in the Chao Phraya basin include Nakhon Sawan, Uthai Thani, Chainat, Singburi, Ang Thong, Ayutthaya, Pathum Thani, Nonthaburi and Samut Prakan.