Callao (kaˈʎao) 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 west of the Historic Centre of Lima.
El Callao was founded by Spanish colonists in 1537, just two years after Lima (1535). The origin of its name is unknown; both Amerindian (particularly Yunga, or Coastal Peruvian) and Spanish sources are credited, but it is certain that it was known by that name since 1550. Other sources point to the similarity with the Portuguese word calhau [pebble], having a similar sound.
It soon became the main port for Spanish commerce in the Pacific. At the height of the Viceroyalty, virtually all goods produced in Peru, Bolivia, and Argentina were carried over the Andes by mule to Callao, to be shipped to Panama, carried overland, and then transported on to Spain via Cuba. The port of Callao was also a node in the Manila galleon route connecting Latin-America and Asia through Acapulco, Mexico and Manila, Philippines. As a result, Callao also became a permanent target for pirate and corsair attacks, such as the one carried out by Francis Drake in 1579 and the blockade established by Jacques l'Hermite in 1624.
After the Battle of Ayacucho, 9 December 1824, that sealed the independence of Peru and South America, Spain made futile attempts to retain its former colonies, such as at the second siege of Callao. On 20 August 1836, during the Peru–Bolivian Confederation, President Andrés de Santa Cruz mandated the creation of the Callao Littoral Province (Provincia Litoral del Callao), which had political autonomy in its internal affairs.