Ubon Ratchathani (อุบลราชธานี) is a city in Isaan, Thailand, in a province of the same name. Often referred to as simply Ubon (อุบล), not to be confused with "Udon Thani" to the north. Ubon lies 582 km from Bangkok and has Thailand's 13th largest city population.
Ubon was founded on the northern bank of the Mun River by a group of Lao princes fleeing Vientiane in the late 1700s. They applied for King Taksin's protection, duly granted in 1779 along with the city's new name, meaning "Royal City of the Lotus". Modern-day Ubon was a U.S. air base during the Vietnam War and grew rapidly at the time, but little has happened since then. The town of Warin Chamrap, on the south bank of the river, is effectively a suburb of Ubon these days.