JOLIET ILL., DIOCESE of. - City and diocese in the State of Illinois, in the United States of America. It comprises the counties of Du Page, Kankakee, Will, Grundy, Ford, Iroquois, and Kendall, all in the State of Illinois.
It has an area of 4,218 square miles, with a population of 355,573 inhabitants, of whom 93,229 are Catholics. It has 73 parishes, 16 missions, 3 chapels; 73 diocesan priests and 130 religious, 16 religious communities, among which is the abbey of S. Procopio at Lisle; it also has 63 communities of women religious. In the diocese there are 5 seminaries and scholasticates with 426 students, 3 Colleges, 2 parish High Schools, and 46 elementary schools; in 1949 there were 422 conversions.
The diocese was created by Pius XII with the apostolic constitution Ecclesiastum circumscriptiones of 11 Dec. 1948, by dismemberment from the archdiocese of Chicago and the dioceses of Peoria and Rockford, raising the church of S. Raimondo Nonnato to cathedral rank. The diocese is suffragan to Chicago.