List of longest-lasting empires

This article is a list of longest-lasting empires organized according to their length of existence. An empire is a state that extends dominion over populations distinct culturally and ethnically from the culture/ethnicity at the center of power. Existence of each empire calculated from when the culture/ethnicity of power took control until that same power lost control of its empire. Some empires have start dates beginning with when the state came into being. Others begin not when the state emerges, but when the culture/ethnicity of power emerges. End dates for empires can be hard to determine. For the convenience of the reader, this article uses the date when the people at the center of power were no longer in formal control of the state due to being overthrown or placed in a position of vassalage to another authority.