During the first half of the 20th century, many Catholic immigrants came from Eastern Europe and Mexico to work in the region's growing steel industry. A number of parishes were founded near the steel mills so that the newly arrived immigrants could celebrate Mass in their native languages. In 1956 the four counties of Lake, Porter, LaPorte, and Starke belonged to the 18 county diocesan territory of the then named Diocese of Fort Wayne. On December 17, 1956, the region was stunned to learn of the announcement that came from they Holy See that a new diocese was to be erected from those four counties in Northwest Indiana and the newly created Diocese of Gary came into existence. On December 29, 1956, Pope Pius XII announced that he had named then Reverend Andrew Gregory Grutka, pastor of Holy Trinity parish, to be the first bishop of the new Gary diocese. The parish of the Holy Angels was selected to become the new cathedral for the diocese, and became the Cathedral of the Holy Angels. The new diocese, at its establishment, found itself with 129 active diocesan priests, 77 parishes, 60 parish schools and 135,485 Catholics, which was roughly 25 percent of the population of the four counties. As of 2012, four parishes in the diocese still offered Mass in Polish, two parishes in Croatian, one in Hungarian, and one in Lithuanian. Fourteen parishes also offered Mass in Spanish. One location offered the 1962 form of the Roman-Rite Mass.
Diocese today
Serving the diocese are 105 priests, 67 permanent deacons, 10 religious brothers, and 85 religious sisters who are members of various religious institutes. These priests, deacons and persons religious serve a Catholic population in northwest Indiana of 186,420 in 73 parishes and missions. The diocese also operates several educational, medical, and social service organizations. Educational institutions include 17 elementary schools, 3 high schools, 1 college, and a Catholic student center at Valparaiso University. The diocese also supervises six hospitals or medical centers, three homes for the aged, three protective homes, three cemeteries, and Catholic Charities, Diocese of Gary. On April 25, 2019, Pope Francis appointed Bishop Donald J. Hying Bishop of Madison and on November 26, 2019, Pope Francis appointed Detroit, Michigan priest Robert John McClory to succeed him. He was both consecrated and installed as Bishop on February 11, 2020.
St. Catherine of Siena, a Catholic elementary school in Hammond, opened prior to 1949. Prior to 2009 its enrollment had declined, with 130 students that year, and its financial state had deteriorated. The school closed in 2009.
, the only Mass in the Extraordinary Form of the Roman Rite in the diocese is offered at the Carmelite Shrine in Munster on Saturday evenings. It was established on Saturday, August 25, 1990, at the recommendation of Bishop Norbert Gaughan. The Mass was featured in newspapers across the country when Summorum Pontificum was promulgated by Pope Benedict XVI. Previously, a Traditional Latin Mass was available at St. Stanislaus in Michigan City on Sundays, but this Mass was discontinued when the celebrant died. St. Joseph the Worker in Gary had a monthly Mass that was a hybrid of the Extraordinary and Ordinary Forms. In 2015, the NWI Latin Mass Community was founded by laity to support and promote the Extraordinary Form in the Gary Diocese, with the particular goals of offering Sunday morning and Holy Day Masses in the Extraordinary Form, as well as fostering parish life for those who are attached to the older form of the Mass. On January 1, 2018, a Solemn High Mass was offered at the Cathedral of the Holy Angels by Bishop Joseph Perry, auxiliary bishop for the Archdiocese of Chicago. In 2018, the Institute of Christ the King began an apostolate at St. Joseph parish in Hammond, offering the Extraordinary Form on a weekly basis. St. Joseph parish in Dyer also holds a monthly mass in the Extraordinary Form.
