The name"Ratchaburi Province" is auspicious, as it translates to "City of the King." It is one of the oldest cities in Thailand. Archaeologists and historians have discovered through excavations and studies that the Mae Klong River basin has been inhabited and flourished by individuals from a variety of eras since ancient times. This region has been inhabited since the Middle Stone Age, as evidenced by the presence of numerous archaeological sites and artefacts. Additionally, that belief has been verified by the recent discovery of the ancient Dvaravati city in the Khu Bua Subdistrict of Mueang Ratchaburi District.

Phra Bat Somdet Phra Phutthayotfa Chulalok Maharat (King Rama I), the founding monarch of the Chakri Dynasty, served as the Luang Yokkrabat of Ratchaburi during the late Ayutthaya period. Ratchaburi was a significant frontier city and battlefield during the late Ayutthaya and early Rattanakosin periods, as indicated by historical evidence. Specifically, the city was a strategic location during the reign of King Rama I, during which he led warriors to defend against Burmese invasions on multiple occasions. The Nine Armies War was the most significant occasion.

In 1817, Phra Bat Somdet Phra Phutthaloetla Naphalai (King Rama II) commissioned the construction of a new city wall on the left bank of the Mae Klong River, which remains in place to this day. Subsequently, in 1894, King Chulalongkorn (Rama V) implemented a reform of regional administration by merging adjacent municipalities into provinces. Ratchaburi Province was established through the consolidation of Ratchaburi, Kanchanaburi, Samut Songkhram, Phetchaburi, Pranburi, and Prachuap Khiri Khan, a total of six cities. The provincial command centre was established in Ratchaburi City, which is situated on the right bank of the Mae Klong River. The Ratchaburi National Museum is presently located at the site that was previously the location of the Ratchaburi City Hall. In 1897, the command centre relocated from the left bank to the right bank of the Mae Klong River, where it connected with the Ratchaburi Provincial Hall. Ratchaburi Province retained its designation as "Ratchaburi Province" until the provincial administration system was abolished in 1933.