The Aisne (/eɪn/ ayn,[1] US also /ɛn/ en,[2] French: [ɛːn] ⓘ; Picard: Ainne) is a river in northeastern France.

Departments and towns along the river include: The river Aisne was used for commercial navigation as early as the Celtic period, and rafts were floated from a long distance above the present limit of navigation at Vailly-sur-Aisne until the mid-19th century.

Canalisation works were begun in 1836, at the same time as construction of the Canal lateral à l'Aisne.

The waterway is 57 kilometres (35 mi) long, from the river Oise to the junction with the lateral canal, and has 7 locks.

[5] The kilometre distances continue the numbering from Canal latéral à l'Aisne from east to west.