| Jurisdiction: | Archdiocese |
| Mercedes-Luján | |
| Latin: | Archidioecesis Mercedensis-Luianensis |
| Local: | Arquidiócesis de Mercedes-Luján |
| Country: | Argentina |
| Metropolitan: | Mercedes-Luján |
| Area Km2: | 19,330 |
| Population: | 712,000 |
| Population As Of: | 2004 |
| Catholics: | 689,300 |
| Catholics Percent: | 96.8 |
| Denomination: | Roman Catholic |
| Rite: | Roman Rite |
| Established: | 20 April 1934 |
| Cathedral: | Cathedral Basilica of Our Lady of Mercy |
| Patron: | Virgin of Mercy Our Lady of Luján |
| Bishop: | Jorge Eduardo Scheinig |
| Bishop Title: | Archbishop |
| Suffragan: | for one --> |
| Archdeacon: | for one--> |
| Website: | Website of the Archdiocese |
The Archdiocese of Mercedes-Luján (Spanish; Castilian: Arquidiócesis Mercedes-Luján; Latin: Archidioecesis Mercedensis-Luianensis) is a Latin Church ecclesiastical territory or archdiocese of the Catholic Church in north-central Buenos Aires Province, Argentina. It was immediately subject to the Holy See, coming into 2019. Erected as the Diocese of Mercedes on 20 April 1934, it was renamed as the Diocese of Mercedes-Luján on 10 May 1989 and elevated to its status as an archdiocese on 21 November 1997. Its mother church is the Catedral Basílica de Mercedes-Luján in Mercedes.
On 4 March 2019, Pope Francis raised it to a metropolitan archdiocese, with three suffragan dioceses within its ecclesiastical province. The suffragan dioceses are Merlo-Moreno, Nueve de Julio, and Zárate-Campana. The first had been in the Buenos Aires province, and the other two were in the La Plata province. Francis also appointed the first metropolitan archbishop, Jorge Eduardo Scheinig, who had been titular bishop of Ita.[1]
The archdiocese serves fifteen partidos in Buenos Aires Province:
| Year | Along with | To form | |
|---|---|---|---|
| 1947 | Archdiocese of La Plata | Diocese of San Nicolás de los Arroyos | |
| 1957 | Diocese of Azul | Diocese of Nueve de Julio | |
| 1957 | Diocese of Bahía Blanca | Diocese of Santa Rosa |