Luján is a city in the Buenos Aires province of Argentina, located 68 kilometres northwest of the city of Buenos Aires. The city was foundeā¦Luján is a city in the Buenos Aires province of Argentina, located 68 kilometres northwest of the city of Buenos Aires. The city was founded in 1755 and has a population of 106,899. Luján is best known for its large, neo-gothic Basilica, built in honor of the Virgin of Luján, the patron saint of Argentina. Every year, more than six million people make pilgrimages to the basilica, many walking there from Buenos Aires. The city is known as La Capital de la Fe. It is a popular day-trip for non-believers too, with abundant grill restaurants and souvenir shops with kitsch religious memorabilia.