Aisne is a French department in the Hauts-de-France region of northern France. It is named after the river Aisne. In 2020, it had a population of 529,374.

In the administrative divisions of France, the department is one of the three levels of government under the national level, between the administrative regions and the communes. Ninety-six departments are in metropolitan France, with an additional five constituting overseas departments, which are also classified as overseas regions. Departments are further subdivided into 333 arrondissements and 2,054 cantons. These last two levels of government have no political autonomy, instead serving as the administrative basis for the local organisation of police, fire departments as well as, in certain cases, elections.