The diocesan territory stretches over a land area of 53,917 square kilometers in Thailand's northeast and covers seven provinces: Amnat Chareon, Mahasarakham, Si Sa Ket, Surin, Roi-et, Ubon Ratchathani and Yasothon. It is a suffragan diocese of the Archdiocese of Tharae-Nongsaeng.
The diocese had a population of 7,747,639 at the end of 2005. The population of the whole country is about 65 million.
The website of Ubon Ratchathani Diocese is available (only in Thai) at:www.catholic.or.th/bishopubon/