Beaucroissant (French pronunciation: [bokʁwasɑ̃]) is a commune in the Isère department in the Auvergne-Rhône-Alpes region of south-eastern France.

A railway from Le Grand-Lemps passes through the commune with a station in the village and continues north-east to Rives.

[8] The commune is famous for its annual fair which has continued since 1219 due to the pilgrimage of Our Lady of Parménie.

The origin of the Beaucroissant fair dates back to 14 September 1219 when the Saint Laurent lake (above the Bourg d'Oisans) overflowed causing a terrible flood that inundated Grenoble and had many victims.

Starting from 14 September 1220, organised by the bishop of Grenoble, survivors commemorated this event with a pilgrimage to Parménie.