Klaeng is a district in the eastern part of
Rayong Province, eastern
Thailand. In the reign of King Chulalongkorn (Rama V), Mueang Klaeng was the 4th class city under Monthon
Chanthaburi. The old Mueang office was located in Ban Laem Mueang, Tambon Paknam Prasae. In 1897 the office was moved to Ban Pho Thong, at the northern side of Wat Pho Thong. In 1908 Mueang Klaeng was downgraded to a district of Rayong Province.