Boulogne Sur Mer is a town in Buenos Aires Province, Argentina. It is in San Isidro Partido and forms part of the Greater Buenos Aires urban conurbation, 26 km (16,25 mi) north of Buenos Aires. It has a population of 89,046 (2001 INDEC census). The town is named after the city of Boulogne-sur-Mer in northern France, where the Argentine general José de San Martín died in 1850.