Mohenjo-daro, one of the most prominent and sophisticated urban centers of the ancient world, has been revealed to be significantly older than previously believed. Recent archaeological excavations and new radiocarbon dating of the site's city walls suggest that the ancient megacity was occupied as early as 2700 to 2600 BC. This groundbreaking discovery pushes the origins of the Indus Valley settlement back by several centuries, challenging long-held timelines regarding the emergence of complex urban life in South Asia.
The findings emerged from a joint mission conducted by the Sindh Directorate General Antiquities & Archaeology (DGAA) and the Sindh Exploration & Adventure Society (SEAS Pakistan). Led by Pakistani archaeologists Dr. Asma Ibrahim and Ali Lashari, alongside Dr. Jonathan Mark Kenoyer from the University of Wisconsin, the team focused their efforts on a massive mudbrick perimeter wall surrounding the western Stupa Mound. The IFLScience report highlights that this new evidence indicates the city was already taking shape before the Egyptians began building the Great Pyramids of Giza.
Redating the Mound of the Dead Men
The ruins of Mohenjo-daro, which translates to the "Mound of the Dead Men," are situated along the banks of the Indus River in the Larkana district of modern-day Sindh, Pakistan. At its zenith, the sprawling metropolis covered over 620 acres and was home to an estimated 40,000 residents. The city is renowned for its advanced civic administration, remarkable water infrastructure including the Great Bath, and elaborate sewage systems that were unparalleled in the ancient world.
Excavated ruins of Mohenjo-daro, with the Great Bath in the foreground and the granary mound in the background. (Saqib Qayyum/CC BY-SA 3.0)
During the recent excavations, researchers reopened trenches originally dug by Sir Mortimer Wheeler in 1950. Wheeler had initially misidentified the massive mudbrick structure as a revetment designed to protect the city from flooding. However, five new radiocarbon dates and a thorough stratigraphic review confirmed that the structure was actually a city wall built in multiple phases. According to the Arab News, pottery and carbon samples from the lowest levels indicate the initial wall was constructed at the end of the Early Harappan or Kot Diji Phase, around 2700-2600 BC.
A Gradual Evolution of Urbanism
The discovery of Kot Dijian pottery in deep coring below the first city wall provides crucial evidence that a substantial early occupation existed before the wall was even constructed. This suggests that Mohenjo-daro did not simply appear suddenly during the Mature Harappan phase, but rather evolved gradually from a pre-existing settlement. The Greek Reporter notes that these findings align with similar evidence from Harappa, another major Indus Valley city, which also exhibits Early Harappan occupation and defensive structures dating to the same period.
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The upper sections of the newly dated wall belong to the Mature Harappan period, beginning around 2600 BC, which corresponds to the city's greatest expansion. The DGAA statement confirmed that the walls were expanded and maintained until at least 2200 BC, demonstrating sustained urban planning and organized civic effort over many generations. Future archaeological investigations aim to trace the complete path of the city wall around the Stupa Mound to locate potential gateways and better understand how the structure functioned.
The Lingering Mystery of Decline
While the origins of Mohenjo-daro are becoming clearer, the reasons for its eventual abandonment remain shrouded in mystery. The city flourished for centuries before falling into ruin sometime between 1800 and 1700 BC. Various theories have been proposed, ranging from catastrophic floods or fires to invasions or disease. However, archaeological evidence for a single, defining cataclysm is scarce.
Many researchers now lean towards the theory that a prolonged megadrought struck the broader region around 1800 BC, leading to the steep decline of the Indus Valley Civilization by devastating the agricultural systems upon which these great urban centers depended. Despite its mysterious end, Mohenjo-daro continues to yield fascinating discoveries from later periods, such as the recent unearthing of a massive hoard of Kushan era coins near the Stupa, proving that the site's history is as complex as the civilization that built it.
Top image: Excavated ruins of Mohenjo-daro, with the Great Bath in the foreground and the granary mound in the background. Source: Nikesh chawla/CC BY-SA 4.0
By Gary Manners
References
Hale, T. 2026. Mohenjo-daro: New Dating Pushes the Ancient Megacitiy's Origins Back by Centuries. IFLScience. Available at: https://www.iflscience.com/one-of-the-earliest-major-cities-in-the-indus-valley-is-even-older-than-thought-83078
Khan, N. 2026. New excavations show Mohenjo-daro, ancient Indus Valley city, is older than thought. Arab News. Available at: https://www.arabnews.com/node/2637253/pakistan
Moeed, A. 2026. New Evidence Dates Ancient Indus Valley City Mohenjo-daro to 3300 BC. Greek Reporter. Available at: https://greekreporter.com/2026/04/03/new-evidence-ancient-indus-valley-city-mohenjo-daro/
