Udon Thani is a city located in the Isan region of Thailand. It serves as the capital of Udon Thani Province and ranks as the sixth largest city in the country.
The city municipality had a population of 130,531 as of 2019, while the broader urban area of Mueang Udon Thani is home to approximately 400,000 people. It is recognized as one of the "big four" major cities in Isan, alongside Nakhon Ratchasima, Ubon Ratchathani, and Khon Kaen.