Glaciers cover approximately 40 square miles (100 square km) of Mont Blanc (whence its name, meaning “white mountain”). Ice streams stretch from the central ice dome down to below 4,900 feet (1,490 m). The Mer de Glace, the second longest glacier in the Alps, reached the elevation of 4,100 feet (1,250 m) in 1930. At the beginning of the 17th century, glaciers advanced to the bottom of the Chamonix Valley, destroying or burying cultivated land and dwellings. Since that time, the glaciers have periodically advanced and retreated.

Scientists P. Martel in 1742, Jean A. Deluc in 1770, and, later, Horace Bénédict de Saussure (Saussure, Horace Bénédict de) first drew attention to Mont Blanc's distinction as western Europe's highest mountain. That designation stirred adventurers to climb the peak. The summit was conquered in 1786 by Michel-Gabriel Paccard, a doctor from Chamonix, together with Jacques Balmat, his porter. Paccard's achievement, one of the most important in the history of mountaineering, was overshadowed by de Saussure's ascent the year after. Through Marc-Théodore Bourrit, who failed the ascent and, out of jealousy, published a biased account of the first ascent, the myth was started that all credit for the climb was due to the peasant Balmat.