“Uthai Thani (Thai อุทัยธานี) is one of the provinces (changwat) of Thailand. Neighboring provinces are (from north clockwise)Nakhon Sawan, Chai Nat, Suphan Buri, Kanchanaburi and Tak.

 The province stretches from the upper plains of the Chao Phraya river valley, to mountains covered with forests in the west. TheSakae Krang River, a tributary of the Chao Phraya River is the main river of Uthai Thani province.” (1)

[1] -http://en.wikipedia.org/wiki/Uthai_Thani_Province