An archdiocese is a substantial religious diocese, typically including a major city, that is governed by an archbishop.
In addition to governing parishes within the city and nearby suburbs, it also has oversight of smaller dioceses. For example, the Archdiocese of San Antonio, Texas, in addition to governance over parishes in the San Antonio area, also oversees the Dioceses of Amarillo, Dallas, El Paso, Fort Worth, Laredo, Lubbock, and San Angelo.