Callao is a Peruvian seaside city and region on the Pacific Ocean in the Lima metropolitan area. Callao is Peru's chief seaport and home to its main airport, Jorge Chávez International Airport. Callao municipality consists of the whole Callao Region, which is also coterminous with the Province of Callao. Founded in 1537 by the Spaniards, the city has a long naval history as one of the main ports in Latin America and the Pacific, as it was one of vital Spanish towns during the colonial era. Central Callao is about 15 km (9.3 mi) west of the Historic Centre of Lima.

The Viceroyalty of Peru, officially known as the Kingdom of Peru, was a Spanish imperial provincial administrative district, created in 1542, that originally contained modern-day Peru and most of the Spanish Empire in South America, governed from the capital of Lima. Peru was one of the two Spanish viceroyalties in the Americas from the sixteenth to the eighteenth centuries.