At its greatest extent, the Inca Empire covered parts of six modern countries.
The empire, known as Tawantinsuyu, stretched along the Andes from southern Colombia through Ecuador, Peru, Bolivia and northern Chile to northwestern Argentina. Its core lay in the central Andes, with Cusco in present-day Peru serving as the imperial capital. The Inca state reached its maximum size in the early sixteenth century, shortly before the Spanish conquest.
The six modern countries are Colombia, Ecuador, Peru, Bolivia, Chile and Argentina. “Parts of” matters: the Inca Empire did not control all of any of these present-day nations, whose modern borders were created long after the empire disappeared.
Another common mistake is counting historical regions rather than modern countries. The empire’s territory is often described as roughly 2 million square kilometres, though estimates vary according to how firmly frontier zones were controlled. It was linked by the Qhapaq Ñan road system and divided administratively into four major regions, or suyus, arranged around Cusco.