Pedro del Castillo (1521 - 28 March 1569) was a Spanish conquistador.
He was born at Villalba de Rioja.
After acting as corregidor in some recently founded American towns, he was in Chile at the orders of Francisco de Villagra, with whom he took part in the Arauco War.[1]
In November 1560 he was appointed by the governor of Chile, García Hurtado de Mendoza, as capitán general y teniente gobernador para poblar, fundar, repartir tierras y encomendar indios en la provincia de Cuyo (commander-in-chief and plenipotentiary for the province of Cuyo), in what is now eastern Argentina. Castillo organized and expedition which crossed the Andes, passing through the Aconcagua and Uspallata velleys, reaching the Huentata valley on 22 February.
On 2 March 1561 Pedro del Castillo founded the city of Mendoza. A few time later, he was sent to Lima, Peru, and afterwards he established himself in Panama. He died at Panama City in 1569.