Inca road system
The Inca road system was the most extensive and advanced transportation system in pre-Columbian South America. It was about long in total. The construction of the roads required a large expenditure of time and effort.
The network was composed of formal roads carefully planned, engineered, built, marked and maintained; paved where necessary, with stairways to gain elevation, bridges and accessory constructions such as retaining walls, and water drainage systems. It was based on two north–south roads: one along the coast and the second and most important inland and up the mountains, both with numerous branches.
It can be directly compared with the road network built during the Roman Empire, although the Inca road system was built one thousand years later.
The road system allowed for the transfer of information, goods, soldiers and persons, without the use of wheels, within the Tawantinsuyu or Inca Empire throughout a territory covering almost and inhabited by about 12 million people.
The roads were bordered, at intervals, with buildings to allow the most effective usage: at short distance there were relay stations for chasquis, the running messengers; at a one-day walking interval tambos allowed support to the road users and flocks of llama pack animals. Administrative centers with warehouses, called qullqas, for re-distribution of goods were found along the roads. Towards the boundaries of the Inca Empire and in newly conquered areas pukaras were found.
Part of the road network was built by cultures that precede the Inca Empire, notably the Wari culture in the northern central Peru and the Tiwanaku culture in Bolivia. Different organizations such as UNESCO and IUCN have been working to protect the network in collaboration with the governments and communities of the six countries through which the Great Inca Road passes.
In modern times some remnant of the roads see heavy use from tourism, such as the Inca Trail to Machu Picchu,which is well known by trekkers.
A 2021 study found that its effects have lingered for over 500 years, with wages, nutrition and school levels higher in communities living within 20 kilometers of the Inca Road, compared to similar communities farther away.
Extent
The Tawantinsuyu, which integrated the current territories of Peru, continued towards the north through present-day Ecuador, reaching the northernmost limits of the Andean mountain range in the region of Los Pastos in Colombia; by the South, it penetrated down to the Mendoza and Atacama lands, in the southernmost reaches of the Empire, corresponding currently with Argentine and Chilean territories. On the Chilean side, the road reached the Maipo river. The Inca Road system connected the northern territories with the capital city Cusco and the southern territories.About, out of the more than that the Andean mountains spans, were covered by it.
As indicated by Hyslop, "The main route of the sierra that passes through Quito, Tumebamba, Huánuco, Cusco, Chucuito, Paria and Chicona to the Mendoza River, has a length of 5,658 km."
The exact extent of the road network is not known: travelers and scholars proposed various lengths, spanning from to to.
Two main routes were defined: the eastern one, inland, runs high in the puna grassland, a large and undulating surface, which extends above ; the second one, the western route, that starts from the region of Tumbes in the current Peru–Ecuador border, follows the coastal plains, but does not include the coastal deserts, where it hugs the foothills. This western road outlines the current Pan-American Highway in its South American pacific extension.
Recent investigations carried out under the Proyecto Qhapaq Ñan, sponsored by the Peruvian government and basing also on previous research and surveys, suggest with a high degree of probability that another branch of the road system existed on the east side of the Andean ridge, connecting the administrative centre of Huánuco Pampa with the Amazonian provinces and having a length of about.
More than twenty transversal routes ran over the western mountains, while others traversed the eastern cordillera in the mountains and lowlands, connecting the two main routes and populated areas, administrative centres, agricultural and mining zones, as well as ceremonial centres and sacred spaces in different parts of the vast Inca territory. Some of these roads reach altitudes of over above sea level.
The four routes
During the Inca Empire, the roads officially stemmed from Cusco into the 4 cardinal directions towards the 4 suyus into which the Tawantinsuyu was divided. Cusco was the center of Peru: the Inca-Spanish chronicler Inca Garcilaso de la Vega states that "Cozco in the language of the Incas means navel that is the Earth's navel".The four regions were named Chinchaysuyu towards the North, Collasuysu towards the South, Antisuyu towards the East and the lower valleys of the Amazon region and Contisuyu towards the West and the lower valleys along the Pacific coast.
The route towards the North was the most important in the Inca Empire, as shown by its constructive characteristics: a width ranging between 3 and 16 m and the size of the archaeological vestiges that mark the way both in its vicinity and in its area of influence. It is not coincidental that this path goes through and organizes the most important administrative centers of the Tawantinsuyu outside Cusco, such as Vilcashuamán, Xauxa, Tarmatambo, Pumpu, Huánuco Pampa, Cajamarca and Huancabamba, in current territories of Peru; and Ingapirca, Tomebamba or Riobamba in Ecuador. This was regarded by the Incas as "the" Qhapaq Ñan, main road or royal road, starting from Cusco and arriving in Quito. From Quito northwards, the Inca presence is perceived in defensive settlements that mark the advance of the Empire by the Ecuadorian provinces of Carchi and Imbabura and the current Nariño Department in Colombia, which in the 16th century was in process of being incorporated into the Inca Empire.
The route of Qollasuyu leaves Cusco and points towards the South, splitting into two branches to skirt Lake Titicaca that join again to cross the territory of the Bolivian Altiplano. From there the roads were unfolding to advance towards the southernmost boundaries of the Tawantinsuyu. One branch headed towards the current Mendoza region of Argentina, while the other penetrated the ancient territories of the Diaguita and Atacama people in Chilean lands, who had already developed basic road networks. From there, crossing the driest desert in the world, the Atacama Desert, the Qollasuyu route reached the Maipo river, currently in the Santiago metropolitan region. From there no vestiges of the Inca advance have been found.
Contisuyu roads allowed to connect Cusco to coastal territories, in what corresponds to the current regions of Arequipa, Moquegua and Tacna, in the extreme Peruvian south. These roads are transversal routes that guaranteed the complementarity of natural resources, since they cross very varied ecological floors, in the varied altitude of the descent from the heights of the cordillera to the coastal spaces.
The roads of the Antisuyu are the least known and a lesser number of vestiges were registered. They penetrated into the territories of the Ceja de Jungla or Amazonian Andes leading to the Amazon rainforest, where conditions are more difficult for the conservation of archaeological evidences. The true physical extension of the Inca Empire for this region is not very clear.
Purposes of the road
The Incas used the road system for a variety of reasons, from transportation for people who were traveling through the Empire to military and religious purposes. The road system allowed for a fast movement of persons from one part of the Empire to the other: both armies and workers used the roads to move and the tambos to rest and be fed. It also allowed for the fast movement of information and valuable small goods which traveled through the chasquis. The Incas gave priority to the straightness of the roads, whenever possible, to shorten the distances.According to Hyslop the roads were the basis for the expansion of the Inca Empire: the most important settlements were located on the main roads, following a provision prefigured by the existence of older roads. The Incas had a predilection for the use of the Altiplano, or puna areas, for displacement, seeking to avoid contact with the populations settled in the valleys, and project, at the same time, a straight route of rapid communication. Other researchers pointed out additional factors that conditioned the location of Inca settlements and roads, such as the establishment of control zones in an intermediate location with respect to the populations and productive lands of the valleys, the requirement of specific goods, and storage needs, which were favored in the high plains of the Altiplano, characterized by low temperatures and dry climates. As an example, the administrative center of Huánuco Pampa includes 497 collcas, which totaled as much as and could support a population of between twelve and fifteen thousand people. Cotapachi included a group of 2,400 collcas far away from any significant village.
Collcas were long-term storage houses, primarily for the storage of grains and maize, which had an extremely long expiration date and made them ideal for long-term storage for the army in the event of conflicts.
According to Hyslop the use of the Inca road system was reserved to authorities. He states: «soldiers, porters, and llama caravans were prime users, as were the nobility and other individuals on official duty… Other subjects were allowed to walk along the roads only with permission…»
Nevertheless, he recognizes that «there was also an undetermined amount of private traffic … about which little is known». Some local structures exist alongside the road which may allow to infer that also private trade traffic was present.
The use of the Inca roads, in the colonial period, after the Spanish conquest of Peru was mostly discontinued. The Conquistadors used the Inca roads to approach the capital city of Cusco, but they used horses and ox carts, which were not usable on such a road, and soon most of the roads were abandoned.
Only about 25 percent of this network is still visible today, the rest having been destroyed by wars, the change in the economic model which involved abandoning large areas of territory, and finally the construction of modern infrastructure, during the nineteenth and twentieth centuries, which led to the superposition of new communication channels in the outline of pre-Hispanic roads.