Auxerre is the capital (prefecture) of the Yonne department and the fourth-largest city in the Burgundy historical region southeast of Paris. Auxerre's population today is about 35,000; the urban area comprises roughly 113,000 inhabitants. Residents of Auxerre are referred to as Auxerrois.

Yonne is a département in the Bourgogne-Franche-Comté region in France. It is named after the river Yonne, which flows through it, in the country's north-central part. One of Bourgogne-Franche-Comté's eight constituent departments, it is located in its northwestern part, bordering Île-de-France. It was created in 1790 during the French Revolution. Its prefecture is Auxerre, with subprefectures in Avallon and Sens. Its INSEE and postcode number is 89.