The Catholic Diocese of Amarillo comprises twenty-six counties in the Panhandle; the southern boundary of the diocese is the line that forms the southern boundary of Childress, Hall, Briscoe, Swisher, Castro, and Parmer counties. In 1993 the Catholics of the area numbered 36,795, about 10 percent of the total population.
White settlers entered the Panhandle after the Indians were removed to Indian Territory in 1875. Priests from New Mexico and Kansas served the few Catholics until the Fort Worth and Denver Railway crossed the Panhandle in 1887, and priests came up from Gainesville, Texas. The first Catholic church in the Panhandle, St. Mary's at Clarendon, was built in 1892 for a congregation of predominantly Irish and German railroad employees. The Sisters of Charity of the Incarnate Word, the first nuns to work in the Panhandle, established a school, St. Mary's Academy, in Clarendon in 1899 and St. Anthony's Sanitarium in Amarillo in 1901. Father David Henry Dunn moved church headquarters from Clarendon to Amarillo, the railroad crossroads, in 1902. At the breakup of the big ranches, Catholic farming parishes were established, largely by settlers of German descent. First among these was that at Nazareth, founded in 1903, and by 1913 there were thirteen such rural Catholic parishes around Amarillo. After irrigation with underground water developed in West Texas, Catholic Hispanic migrant laborers moved to the area. When the gas and oil industry grew in the Panhandle and the Permian Basin, Catholic parishes were formed in the oil towns of Borger and Pampa.
In 1926 the church responded to the influx of people by establishing the Diocese of Amarillo, which included the Panhandle and the area as far south as Kimble, Sutton, and Crockett counties, for a total of 70½ counties. The first bishop, Rudolph A. Gerken (1927–33), built churches and schools and founded Price Memorial College, now Alamo Catholic High School. The diocesan Catholic Charities opened in 1932. Bishop Robert E. Lucey (1934–41) established the diocesan newspaper in 1936. A mission to black Catholics was opened in 1940. A diocesan Council of Catholic Women was organized. When Lucey was made archbishop of San Antonio in 1941, Bishop Laurence J. FitzSimon replaced him in Amarillo. After World War II West Texas experienced a surge in economic growth, which the church shared. Facilities expanded. Hispanic families coming to work in cotton and vegetable fields settled down in towns. Between 1945 and 1965, forty predominantly Hispanic parishes were established in the Lubbock area alone. FitzSimon established a Catholic Children's Home in the town of Panhandle. When FitzSimon died in 1958, John L. Morkovsky, auxiliary bishop since 1955, was made bishop of Amarillo. During his tenure (1958–63) St. Ann's Nursing Home was built in Panhandle. New demographics, however, reduced the size of the diocese. Growth led to the establishment of the Diocese of San Angelo in 1961, when the 21½ southernmost counties of the Diocese of Amarillo were transferred to the new diocese.
Morkovsky, transferred to the Diocese of Galveston-Houston, was followed in 1963 in Amarillo by Bishop Lawrence M. DeFalco, who introduced reforms issuing from the Second Vatican Council. A Diocesan Pastoral Council, a Priests' Senate, and a Sisters' Council were formed. By authority of Vatican II the permanent diaconate, which had fallen into disuse in the church centuries earlier, was reestablished. During the same period a program for refugees was developed, and St. Joseph's Home for retired priests was built in Panhandle. After the death of Bishop DeFalco in 1979, Leroy T. Matthiesen became bishop of Amarillo in 1980. He built the Bishop DeFalco Retreat Center, brought contemplative Franciscan nuns to Amarillo, and established the seminary of Missionaries of Christ the Priest. He also had the Museum-Archives Building constructed.
In 1983 the twenty-three southern counties of the diocese were transferred to the new Diocese of Lubbock. In 1993 the Diocese of Amarillo included forty-two parishes and missions and seventeen chapels, served by sixty-eight priests and thirty permanent deacons. One religious brother and 154 religious sisters worked in the diocese. The diocese had one Catholic high school and eight elementary schools.