Francisco López de Osornio Merlo (1681 – 1756) was a Spanish military leader and landowner, who served during the Viceroyalty of Peru as Captain of the provincial militias of Buenos Aires.

[1] He was born on September 7, 1681, in Buenos Aires, the son of Francisco López Osornio and Tomasa Merlo, belonging to an illustrious family of Spanish and Creole origin.

[3] His son Clemente López de Osornio, a landowner belonging to the Spanish Army, died assassinated during an indigenous incursion to the Province of Buenos Aires.

[4] He had an active participation in the military expeditions aimed at controlling the indigenous advance towards the Province of Buenos Aires.

[5] In 1726 he had served as commander of the Fort of Barragán, place where had ordered the construction of the first chapel.