[5] At one time it was thought that the early town was founded on the coast of the Gulf of Thailand, and that over time the coast had moved 30 km (18 miles) away to the south, due to sedimentation coming down the Mae Klong River.

[6] However, geological and palynological investigation has shown that these early Dvaravati and proto-Dvaravati towns were all inland, at the edges of swamps when founded.

Archeological discoveries show that the area was already settled in the Bronze Age, and the town itself is known to have existed for at least two thousand years.

In the 13th-century, King Ram Khamhaeng seized Ratchaburi and incorporated it into the Sukhothai Kingdom.

[9] In 1768 the Burmese (who had recently destroyed Ayutthaya) were thrown out of Ratchaburi by King Taksin, and the town became part of Siam.