Ubon Ratchathani is one of the four main cities in Thailand's Isan region, alongside Nakhon Ratchasima (Khorat), Udon Thani, and Khon Kaen, collectively known as the "big four of Isan." Located on the Mun River in the southeastern Isan, Ubon Ratchathani sits about 615 km (382 mi) from Bangkok. Commonly shortened to Ubon (อุบลฯ), the city’s name means "royal lotus city". It serves as the administrative center of Ubon Ratchathani Province.