Why are passes through the Central Pyrenees difficult to cross?

Passes through the Central Pyrenees are difficult to cross primarily due to the extreme elevation and rugged topography of the region. Unlike the western sector of the mountain chain, where the peaks are lower and more accessible, the Central Pyrenees feature a succession of mountains that rise nearly 9,800 feet (3,000 metres).1

The difficulty is compounded by the following factors:

• High Elevation: The central axis of the range contains the highest peaks, such as Aneto Peak, which reaches 11,169 feet (3,404 metres). Throughout the central region, there are very few locations where the chain can be crossed through passes lower than 6,500 feet (2,000 metres).12
• Complex Structure: The range in this area is characterized by a massive, wide structure—reaching up to 80 miles in width—comprising parallel zones of axial massifs, interior ridges, and pre-Pyrenean folds. This creates a formidable wall that has historically served as a significant barrier between France and Spain.13
• Limited Infrastructure: Due to this challenging terrain, the region lacks major highways or extensive railroad networks, further isolating the area from primary transportation routes.4