The summit of Mont Blanc de Courmayeur is marked as lying entirely within Italy on the Italian Istituto Geografico Militare (IGM) map, while on the French Institut Géographique National (IGN) map the summit lies on the border between France and Italy. A demarcation agreement, signed on 7 March 1861, defines the local border between France and Italy. Currently this act and the attached maps (showing the border on the top of Mont Blanc, 4810 m) are legally valid for both the French and Italian governments.