Peru, country in western South America. Except for the Lake Titicaca basin in the southeast, its borders lie in sparsely populated zones. The boundaries with Colombia to the northeast and Brazil to the east traverse lower ranges or tropical forests, whereas the borders with Bolivia to the southeast, Chile to the south, and Ecuador to the northwest run across the high Andes. To the west, territorial waters, reaching 200 miles (320 km) into the Pacific Ocean, are claimed by Peru.

Peru is essentially a tropical country, with its northern tip nearly touching the Equator. Despite its tropical location, a great diversity of climates, ways of life, and economic activities is brought about by the extremes of elevation and by the southwest winds that sweep in across the cold Peru Current (or Humboldt Current), which flows along its Pacific shoreline. The immense difficulties of travel posed by the Andes have long impeded national unity. Iquitos, on the upper Amazon, lies only about 600 miles (965 km) northeast of Lima, the capital, but, before the airplane, travelers between the cities often chose a 7,000-mile (11,250-km) trip via the Amazon, the Atlantic and Caribbean, the Isthmus of Panama, and the Pacific, rather than the shorter mountain route.