Tracing an Ancient Communication Network

Arizona’s desert holds layers of history, some well-documented, others still to be understood. You’re reading this post because of the digital networks that have been created to keep us connected however before fiber-optic cables and satellites, some human civilizations relied on a different kind of system—one that used the land itself as a means of transmitting messages. Over the past several months, I’ve been retracing one of these systems on foot and by dirt bike, covering miles of rugged terrain to link a series of ancient high points stretching from the northern edge of the Phoenix metro to sites within the Agua Fria National Monument about an hours drive north, each positioned with purpose.

The Hohokam thrived in what is now central and southern Arizona from roughly 300 to 1450 AD. Best known for their canal systems, they also built hilltop settlements—some defensive, others positioned in ways that suggest they were used for signaling. The use of hilltop signaling has been documented in this region, showing that these sites were part of an established communication system. My work isn’t about discovering something new but rather connecting groups of sites that haven’t been linked together in the literature. These high points, often fortified with stone walls, gave commanding views of the surrounding landscape, making them ideal for spotting movement or relaying information.

My desert rambles started with well-documented sites found in academic literature but took on new significance when I realized that several sites spanning from the northern end of Phoenix to Agua Fria had direct lines of sight to one another, forming a potential chain of communication. Unlike common assumptions that these sites are always positioned at the highest peaks, I found that some were placed at mid-elevation points, suggesting that strategic visibility mattered more than sheer altitude.

To verify these connections before venturing out into the desert, I used a combination of software like Peakfinder AR and Gaia GPS locations of each site and then cross-referencing to determine whether they were visible from the next vantage point in the chain. This approach has helped refine my understanding of how these locations may have been selected—not just for their defensive advantages but for their ability to maintain visual links over long distances.

These places follow a pattern: perched on high ridges or carefully positioned hillsides, they provide unobstructed views and sit near reliable water sources. Their locations seem intentional as if selected to keep sightlines open between distant points. Standing on these peaks, scanning the horizon, I can almost imagine a signal fire flickering to life, a message jumping across the valleys.

Communication still depends on elevation. Today’s cell towers are placed on high points for maximum coverage, just as past people likely chose the tallest ridges for their signaling sites. However, not all modern towers are built on the highest peaks—many are strategically placed for accessibility, maintenance, and network efficiency, just as ancient signaling sites needed to be reachable by those tending fires or sending messages. Both systems rely on a balance between elevation and practicality, ensuring that signals can travel efficiently while still being maintained by people on the ground.

The logic hasn’t changed—only the technology has. Just like ancient networks, modern communication systems have gaps and failures. If one node in a network goes down, the message doesn’t get through. The same would have been true for those using these hilltop sites centuries ago. Understanding how these past systems functioned provides insight into the continuity of human communication strategies, even as the methods evolve.

This project isn’t just about checking sites off a map—it’s about reconstructing a system that once shaped how people moved and communicated across this landscape. As part of my research, I’ve been capturing video and photography to document these sites visually, scouting for future work that might further explore these connections. The ability to see these places from both the ground and the air helps piece together the bigger picture of how these networks functioned.

The more I walk these old routes, the more I think about how we conceptualize the past. We often see history as something distant, static, locked behind glass in museums, or buried under layers of time. But what if we thought of the past as something still present, still shaping the way we interact with the world? These networks may no longer be used for signaling, but they are still here, part of the land, part of the way we move through it. Maybe the biggest difference between then and now isn’t just technology—it’s how we choose to see what came before us.