Udon Thani diocese covers 50,046 square kilometers and includes Thailand's civil provinces of Udon Thani, Nongkhai, Khon Kaen, Loei and Nong Boa Lamphu. It is a suffragan diocese within the Eccleciastical Province of Tharae-Nongsaeng.
Udon Thani became an apostolic prefecture on May 7, 1953, and was made a diocese on Dec. 18, 1965. Redemptorist Bishop Clarence Duhart was named its first bishop on Dec. 18, 1965, the same day it assumed diocesan status. The American-born missioner, who resigned on Oct. 18, 1975, was the main consecrator of his successor, Bishop George Yod Phimphisan, on Dec. 12, 1975. The cathedral of the diocese is consecrated to the Blessed Mother, Our Lady of Perpetual Help.
The website of Udon Thani Diocese is available (only in Thai) at: www.udon-diocese.cbct.org