5,000 Holes on a Peruvian Hillside? Why Scientists Now Think This Was an Ancient Accounting System

Initially, the hillside looks puzzling. There is a hill in Pisco Valley, Peru, where thousands of small holes have been carved. These holes have been arranged in straight lines, evenly spaced, covering almost a mile along the hill. They look purposeful, though not easily comprehensible.

For a long time, no one really agreed on what it was.

Some believed the site had a ritual purpose. Others thought it might be symbolic. But newer research is pointing in a different direction, something far more practical.


It may have been used to keep track of goods.

A Hillside That Functioned Like a Record System

A study titled Indigenous Accounting and Exchange at Monte Sierpe, published by Cambridge University Press, has pushed this idea forward. When researchers looked closely at how the pits were arranged, they noticed patterns that did not look random.

There are more than 5,000 holes. They are not scattered. They follow sequences that suggest counting.

That alone raised questions, but what was found inside some of the pits made the argument stronger.

Scientists identified tiny plant remains in the soil. These included traces of maize and fibers linked to weaving. That detail matters. It suggests that physical items were once placed inside the pits.

So the holes were not just carved and left empty. They were used.

Instead of being symbolic, the site may have helped track real things. Food supplies, raw materials, and possibly even goods collected as part of tribute.

Research in Antiquity suggests that the layout could embody a counting logic similar to the Inca khipus. The difference is that the khipus were portable, and this system is embedded in the landscape.

Aside from the use of the layout for storage, it also had a function for movement. In order to understand the significance of this, it’s important to take a step back.

Large societies need ways to manage resources. They need to know what is coming in, what is going out, and what is being stored.

The Inca are known for using knotted cords for record keeping. But Monte Sierpe suggests that not all systems were small or portable. Some may have been built to be shared and seen.

Research highlighted by the University of South Florida notes that the site sits between important regional areas. It is also close to routes that connect different parts of the Andes.

That placement is unlikely to be accidental.

Goods moving between regions may have been counted or organized here. Crops, textiles, and other materials could have been tracked before being moved again.

The hillside was not simply a backdrop but likely also affected the allocation and utilization of resources.

Stepping Beyond Guesswork

It is because of its unusual appearance that this site has prompted a flood of theories over the years, many of them leading down a mysterious path.

But recent work relies on evidence instead.

The patterns can be measured. The plant remains can be tested. The location fits with what is already known about trade and movement in the region.

Reporting from National Geographic explains how soil and botanical analysis have helped connect the pits to everyday activities like storage and exchange.

Taken together, these details point in a clear direction.

The site reflects planning, not guesswork.

Monte Sierpe states that records may not necessarily be written in ink and paper form. In some cases, it may have a physical form that blends in with its surroundings.

But once this concept becomes clear in one’s mind, everything looks different from what it initially looked like.

No longer mystified by it, it becomes a system that people are familiar with and use in their daily lives.