San Nicolás de los Arroyos (usually shortened to San Nicolás) is a city in the province of Buenos Aires, Argentina, on the western shore of the Paraná River, 61 km (38 mi) from Rosario. It has about 138,000 inhabitants (2001 census [INDEC]). It is the administrative seat of the partido of the same name. It is sometimes called Ciudad de María (City of Mary) due to a series of Marian apparitions recorded since the 1970s.