The Diocese of Houma–Thibodaux is a Latin Church ecclesiastical territory or diocese of the Catholic Church in southeastern Louisiana. It covers Terrebonne, Lafourche, and the eastern part of St. Mary parishes, Morgan City, and Grand Isle in Jefferson Parish. Although a small diocese in terms of area, it has a large Catholic population, with approximately 126,000 Catholics out of a total population of 202,000. The diocese includes part of Cajun Louisiana.