Inca Road System: The Qhapaq Nan Across the Andes

The Inca road system, known in Quechua as the Qhapaq Nan (“royal road”), was a network of roads that ran for an estimated 30,000 km across the Andes and along the Pacific coast of South America. Built and expanded mainly in the 15th and early 16th centuries, it linked Cusco with every corner of the Inca Empire, from southern Colombia to central Chile. With its suspension bridges, way stations and relay runners, it allowed the Incas to move armies, goods and information across some of the most difficult terrain on Earth.

Origins

The Incas did not start from nothing. Earlier Andean states, especially the Wari Empire of the 7th to 11th centuries, had built roads linking their centres, and regional peoples maintained paths between valleys and the coast. The Incas incorporated many of these routes into their network.

Most of the system, however, was built or rebuilt as the empire expanded after the rise of Pachacuti, conventionally dated to around 1438. His successors Topa Inca Yupanqui and Huayna Capac extended it to the farthest frontiers, and work was still continuing when the Spanish arrived in 1532.

The network

The road system had two main trunk routes running roughly north to south:

• The highland road ran along the Andes from the region of Quito in modern Ecuador through Cusco to the Lake Titicaca basin, then south into what are now Bolivia, Argentina and Chile. It is often considered the Qhapaq Nan proper.
• The coastal road ran along the Pacific desert coast from northern Peru southwards, crossing the river valleys that cut through the desert.

Many transverse roads connected these two routes, climbing from the coast to the highlands and descending east towards the Amazon forest edge. Smaller roads led to mines, shrines, farms and royal estates, including the famous stone path now walked as the Inca Trail to Machu Picchu.

The American archaeologist John Hyslop, who surveyed the roads in the late 1970s and early 1980s, recorded some 23,000 km of road and estimated the whole network at a larger figure. Modern estimates typically range between about 30,000 and 40,000 km.

Engineering the Andes

The roads crossed deserts, high plateaus, cloud forests and passes above 4,500 m, with some routes rising higher still. Inca engineers adapted their construction to each environment.

• Width and paving. Roads varied from about 1 m wide on mountain slopes to more than 10 m near major centres. In the highlands, many were paved with fitted stones; in the desert, they were often simply cleared and lined with low walls or rows of posts.
• Stairways and switchbacks. On steep slopes, roads climbed by long flights of stone steps. Because the Incas had no wheeled vehicles and used llamas and people as carriers, steps were practical.
• Drainage and retaining walls. Culverts, gutters and terraced walls protected roads from rain and landslides.
• Causeways. Raised causeways carried roads across marshy ground, especially near Lake Titicaca.

The most dramatic feature was the suspension bridge. Woven from grass ropes, these bridges spanned deep gorges and were rebuilt regularly by local communities as part of their labour duty. The bridge over the Apurimac River near Cusco became famous among the Spanish. One bridge of this kind, Q’eswachaka, is still rewoven every year by Quechua communities in the Cusco region; its tradition was recognised by UNESCO in 2013 as Intangible Cultural Heritage.

Tambos, storehouses and chasquis

Along the roads, the state built tambos, way stations spaced roughly a day’s walk apart, often about 20–30 km. They provided lodging, food and supplies for officials, soldiers and travellers on state business. Some grew into large administrative centres, such as Huanuco Pampa in the central highlands, with hundreds of buildings.

Near many tambos stood rows of storehouses called qollqa, filled with maize, potatoes, dried meat, cloth and weapons. Thousands of these storehouses supplied armies on the march and supported people in times of hardship.

Messages travelled by chasquis, relay runners stationed in small posts every few kilometres along the main roads. Each runner sprinted to the next post and passed on a spoken message or a khipu, a set of knotted cords used for records. Chroniclers were struck by the speed of the system, and modern estimates for the distance a message could cover in a day range from about 200 to 250 km, far faster than any single traveller.

A road for the state

The Qhapaq Nan was not a public highway in the modern sense. It belonged to the state. Armies, officials, tribute caravans, labourers on state service and religious processions used it, and ordinary people generally needed permission to travel. Toll points at bridges and checkpoints controlled movement.

Maintenance was a duty of the communities through which the roads passed, organised as part of the mit’a labour tax. This allowed the Incas to maintain a vast network without paid workers or money.

The roads also had a sacred dimension. Pilgrimages and ceremonies used them, including the capacocha rituals, in which offerings, sometimes including children, were carried from Cusco to sacred mountains at the edges of the empire.

The road after the conquest

In 1532 Francisco Pizarro and his small force marched inland along Inca roads to meet the ruler Atahualpa at the Battle of Cajamarca. The roads that had held the empire together now carried its conquerors, and Spanish horses moved quickly on their well-built surfaces.

Under colonial rule, many roads fell into disrepair. Horses and mules damaged stone steps that had been designed for people and llamas, the tambo system broke down and new colonial routes favoured links to Spanish towns and mines. Yet many sections continued in local use, and some remain in use today.

Rediscovery and World Heritage

Since the late 20th century, archaeologists and governments have surveyed and protected the roads. In June 2014 UNESCO inscribed “Qhapaq Ñan, Andean Road System” as a World Heritage Site, a joint nomination by Argentina, Bolivia, Chile, Colombia, Ecuador and Peru. The listing covers several hundred kilometres of selected road sections and hundreds of associated archaeological sites.

By the numbers

Llamas were the only pack animals on the roads. A llama can carry a load of roughly 25–30 kg, so large caravans of hundreds of animals moved goods between storehouses. Most heavy burdens, however, were carried by people, which is why steps and steep paths were acceptable to Inca builders in a way they would not have been for wheeled traffic.

Timeline

• c. 600–1000: Wari state builds roads in the central Andes.
• c. 1438 (traditional): Pachacuti comes to power and Inca expansion accelerates.
• c. 1463–1493: Topa Inca Yupanqui extends roads to Ecuador, Chile and Argentina.
• c. 1493–1527: Huayna Capac extends the northern roads towards Colombia.
• 1532: Pizarro’s expedition marches along Inca roads to Cajamarca.
• 1984: John Hyslop publishes his survey of the Inca roads.
• 2014, June: UNESCO lists the Qhapaq Nan as a World Heritage Site.

Why it matters

The Qhapaq Nan was the backbone of the largest state in the pre-Columbian Americas, allowing a government without writing in the usual sense, money or wheeled transport to rule millions of people over thousands of kilometres. It remains a remarkable example of engineering in extreme environments, and its surviving paths and bridges still connect Andean communities today.