The "arrondissement" of Châlons-en-Champagne is the central "arrondissements" of the Marne department. It is bordered to the north by the "arrondissement" of Reims and, for a short distance, by the Ardennes department; to the northeast by the Sainte-Menehould "arrondissement"; to the southeast and south by the Vitry-le-François "arrondissement"; and to the west by the Épernay "arrondissement".