Phetchaburi, town, south-central Thailand, located in the northern portion of the Malay Peninsula. It lies 65 miles (105 km) southwest of Bangkok. Phetchaburi is located near the mouth of the Phet Buri River and lies along the southern railway and highway. Before the sea route around the Malay Peninsula was developed, the town was on an overland trade route from Europe and India to continental Southeast Asia. Near the town are the ruins of old Brahmin and Buddhist temples and caves; Khao Luang cave is a Buddhist shrine. Both King Mongkut and his son, Chulalongkorn, built palaces in Phetchaburi. Haad Chao Samran, a popular beach, is nearby. Rice is grown on irrigated land in the surrounding area, and there are coconut, melon, and palm-sugar plantations. Pop. (2000) town, 40,259.