Mercedes (Spanish pronunciation: [meɾˈseðes]) is a city in Buenos Aires Province, Argentina.

Its original name was "La Guardia de Luján" and it was one of several fortress built in the borders of Buenos Aires to protect this city and gather the people living in the county near.

It became a town on 25 June 1752 when founded by José de Zárate during a military campaign known as "La Valerosa".

Mercedes is one of the few towns in Argentina in which three different railways meet, thus been connected with large commercial areas as Buenos Aires as well as the Pacific Ocean, the Andes range and the pampas plains.

This was a powerful reason during the 19th century for proposing the city as the capital of Buenos Aires Province.

The city can also be reached from San Antonio de Areco after completing 50 km-length (31 km) by Provincial Route 41.

On the outskirts of Mercedes there is an old pulpería or rural bar and store, institutions which enjoy mythical status in gaucho culture.

There is an original wanted poster for the outlaw Juan Moreira and reminders of gauchos, their culture and knife fights.