Decize is a commune in the Nièvre department in central France.

The Loire at this point is an important navigation point as it forms the junction between the Canal du Nivernais and the Canal latéral à la Loire both of which are within the town boundaries.

Decize is an ancient settlement first noted in the Commentarii de Bello Gallico where Julius Caesar settled a dispute involving the Decetiae from whom comes the town's name—in Roman times the town’s name was Decetia in Gallia Lugdunensis.

[4] In later times it belonged to the counts of Nevers, from whom it obtained a charter of franchise in 1226.

[5] In 2011 a new port for pleasure boats in the "Bassin de la Jonction" between the Lateral Canal and the Loire was opened.