The most important river that flows into the Gulf of Thailand is the Chao Phraya. This magnificent river flows right past the Royal Palace and main historic wats of modern Bangkok, considerably enhancing the grandeur of the Thai capital. Though at 372 kilometres it is not one of Asia’s, or even Thailand’s, longest rivers, it has had a tremendous influence on Thai history. Its name translates loosely as the “Grand Duke”, reflecting its significance in the history of the kingdom.The Chao Phraya also has numerous important tributaries. It is itself the product of the confluence of two of Thailand’s longest rivers- the Ping and the Nan.
The Ping links Northern and Central Thailand. Rising in the mountains around Chiang Mai, it flows through the Lanna capital, passing the city of Tak and the Sukhothai-era city of Kamphaeng Phet on the way to Nakhon Sawan, where it joins the Nan. The Nan rises in the Luang Prabang Range in the province of Nan and passes through the pilgrimage town of Phitasanulok on its journey to Nakhon Sawan, where it joins the Ping. At 627 kilometres, it is one of Thailand’s longest rivers in itself.
Another of the Chao Phraya’s important tributaries is the Pa Sak River, which rises in the mountainous province of Phetchabun. The Pa Sak River makes an epic journey of 513 kilometre to the alluvial lowlands of the Chao Phraya basin, joining the Chao Phraya at the former Thai capital of Ayutthaya. Its back swamps were probably fertile rice-growing territory in the past and one of Thailand’s significant ancient towns, Si Thep, was found in the Pa Sak River basin.
One of many more tributaries that have been of importance in the history of Thailand is the Tha Chin River. This river splits off from the Chao Phraya and flows through Saphanburi before reaching the province of Nakhon Pathom. The alluvial lowlands of the Tha Chin in Nakhon Province were the historical core of the Dvaravati kingdom– an ethnically Mon kingdom which had a large artistic and cultural influence on both the Khmers and Thais. Anyone wanting to understand the history of Thailand should spend some time studying the Chao Phraya and its tributaries, which were the highways of Central Thailand from antiquity until the modern era.