The arrondissement of Lons-le-Saunier is an arrondissement of France in the Jura department in the Bourgogne-Franche-Comté region.

[2] Its population is 104,178 (2021), and its area is 2,271.9 km2 (877.2 sq mi).

[4] In May 2006 it gained the canton of Chaumergy from the arrondissement of Dole, and it lost the canton of Villers-Farlay to the arrondissement of Dole.

[5] As a result of the reorganisation of the cantons of France which came into effect in 2015, the borders of the cantons are no longer related to the borders of the arrondissements.

The cantons of the arrondissement of Lons-le-Saunier were, as of January 2015:[6]