The 1860 act and attached maps are still legally valid for both the French and Italian governments. In the second half of the nineteenth century, on surveys carried out by a cartographer of the French army, Captain JJ Mieulet, a topographic map was published in France, which incorporated the summit into French territory, making the state border deviate from the watershed line, and giving rise to the differences with the maps published in Italy in the same period.Watershed analysis of modern topographic mapping not only places the main peak on the border, but also suggests that the border should follow a line north from the main peak towards Mont Maudit, leaving the south-east ridge at Mont Blanc de Courmayeur entirely in Italy.