Roman Catholic Diocese of Avellaneda-Lanús Tags: Clerical Administrative Region, Diocese.The Latin Rite Catholic Diocese of Avellaneda-Lanús (erected 10 April 1961 as the Diocese of Avellaneda) is in Argentina and is a suffragan of the Archdiocese of Buenos Aires. It was renamed on 24 April 2001. area (km2) 9.8e+07 country Argentina Established 10 April 1961 ( years ago) province Roman Catholic Archdiocese of Buenos Aires Learn more... Loading...