Udon Thani (Thai: อุดรธานี, [ʔudɔːn tʰaːniː]) is one of the four major cities (Khorat, Ubon Ratchathani, Udon Thani, and Khon Kaen) of the Isan region, Thailand, (known as the "big four of Isan"). It is the capital of Udon Thani Province.
Udon's geographical location 17°25′N 102°45′E is approximately 560 km from Bangkok. Udon is a major official and commercial center in northern Isan, Thailand, and the gateway to Laos, northern Vietnam, and southern China.
The city's economy was boosted by the proximity to Udorn Royal Thai Air Force Base during the Vietnam War and retains reminders of that time in the form of bars, coffee shops, and hotels. "Udon sort of became like Pattaya when the GIs arrived," said a local architect...Restaurants serving Western cuisine, hotels and nightclubs sprouted up everywhere to meet their needs. It was an extremely busy city back then."
Udon also became the site of a Voice of America relay station alleged to have been a CIA black site.
Udon Thani has a tropical savanna climate (Köppen climate classification Aw). Winters are fairly dry and very warm. Temperatures rise until April, which is hot with the average daily maximum at 36.3 °C (97.3 °F). The monsoon season runs from late-April through early-October, with heavy rain and somewhat cooler temperatures during the day, although nights remain warm. The range of reliably recorded temperatures in the city is from 2.5 °C (36.5 °F) to 43.9 °C (111.0 °F).
The city alone has 399,535 inhabitants (out of the provinces 1,572,786).
In the mid-1900s, about 46,700 Vietnamese war refugees migrated to Udon Thani. Their descendants still reside in Udon Thani. Today, Udon Thani has the largest Vietnamese community in all of Thailand.
Asia Pacific Resources, a wholly owned subsidiary of Italian-Thai Development PLC, owns the concession to the Udon Thani potash mines and plans to develop them. According to press reports, Udon Thani has enough potash to mine two million tonnes per year for 25 years. Potash is one of the main components of fertilizer.
Udon Thani has three Tesco Lotus stores, two Big C malls, a Makro, and three large shopping malls. The largest shopping mall is CentralPlaza Udon Thani which hosts Udon Thani's largest movie theatre cinema Major Cineplex. CentralPlaza Udon Thani was reopened 27 March 2012 after a massive renovation and expansion. Landmark Plaza has the second largest cineplex in Udon Thani, SF Cinema City. The shopping mall, UD Town, opened in winter 2009. In a park-like setting on an area of 38,000 m² (24 rai), UD Town is Thailand's largest open air shopping center (Chatuchak market in Bangkok may possibly come a close second in size).
Some of the revenue from tourism is related to tourists going to and/or coming from the archaeological site Ban Chiang (forty-seven kilometres from the city).