Justo Pastor Lynch (1755–1830), an Argentine landowner, was born in Buenos Aires on the family "estancia", a ranch by the River de la Plata.

At times his name was recorded as Pastorin or Pastorino Lynch in reference to the large pastoral land owned by his family dedicated to horses and livestock.

Justo's fortune was one of the largest in the region, properties, and business he received from his family, in addition, he married the Spanish heiress Ana Bernardo Roo (d.1836), who doubled the extent and value of his properties; consequently, his sons enjoyed a wealthy life like no other Irish immigrants in the region.

Another son Estanislao Lynch, born 1793, fought in the Argentine independence war with the grade of colonel.

On 2 January 1817 the Buenos Aires city council appointed Estanislao as the mayor of Barracas.