The Indus Valley Civilization (IVC) was a Bronze Age urban civilization in northwestern South Asia whose Mature phase is dated to about 2600–1900 BCE, with earlier village and proto-urban antecedents and later regional continuities into the second millennium BCE. Its extent stretched from Balochistan to western Uttar Pradesh and from northern Afghanistan to Gujarat, making it among the most extensive early Old World civilizations. Britannica. Early antecedents are documented at Harappa, where deposits reach back to around 3300 BCE. Harappa.com.

Recovery, chronology, and extent

Archaeologists first identified the civilization at Harappa (Punjab, Pakistan) in 1921 and soon after at Mohenjo-daro (Sindh, Pakistan) in 1922, with Sir John Marshall publicly announcing the discovery in September 1924. Britannica; Harappa.com. The Mature Harappan urban florescence is conventionally placed ca. 2600–1900 BCE; the civilization’s settlement area ranged from Sutkagen Dor near the Arabian Sea to sites along the Yamuna basin, with large cities and many smaller towns and villages. Britannica; Britannica.

Urban planning and architecture

Indus cities were laid out on rectilinear grids with major divisions between elevated citadel mounds and lower towns, featuring baked-brick architecture, covered drains, soak-pits, and street-aligned house frontages with bathroom spaces, revealing sophisticated civic planning. UNESCO World Heritage Centre; Britannica. The Great Bath of Mohenjo-daro, a waterproofed brick tank within the citadel complex, illustrates advanced construction and the social importance of controlled water use. Britannica. Cities employed standardized fired bricks with a characteristic 1:2:4 thickness:width:length proportion across sites and periods of the Mature phase. Harappa.com; Kenoyer (chapter summary, Cambridge University Press).

At Dholavira (Khadir Bet, Gujarat), extensive stone architecture, a tripartite urban plan, and a large, integrated water management system of reservoirs and channels demonstrate adaptations to arid conditions; the site was inscribed on the UNESCO World Heritage List in 2021. UNESCO World Heritage Centre; The Indian Express. Lothal (Gujarat), a smaller site on the Gulf of Khambhat, includes a large, brick-lined basin identified by the Archaeological Survey of India and UNESCO as a tidal dockyard associated with a warehouse and bead-making workshops, though some scholars have debated the “dock” interpretation. UNESCO Tentative List; journal://American Anthropologist|The Harappan "Port" at Lothal: Another View|1968.

Economy, agriculture, and craft production

The IVC economy combined intensive agriculture with craft specialization and regional trade. Archaeobotanical and artifact evidence indicates cultivation of wheat and barley with field peas, mustard, sesame, dates, and some of the earliest known use of cotton in South Asia. Britannica. Indus artisans produced standardized carnelian beads, shell and faience ornaments, copper-bronze tools, and finely made ceramics, supported by standardized weight systems used across the region. Britannica; Kenoyer (chapter summary, Cambridge University Press).

Long-distance networks linked the Indus to Mesopotamia, Dilmun (Bahrain), and Magan (Oman), with Mesopotamian texts referring to “Meluhha,” widely identified by scholars with the Indus region; materials such as carnelian, shell, and timber traveled along Gulf routes. Britannica; Institute for the Study of Ancient Cultures, University of Chicago. A Late Akkadian cylinder seal from Mesopotamia naming “Shu‑ilishu, interpreter of the Meluhhan language,” provides direct epigraphic evidence of Indus–Mesopotamian contact. Penn Museum Expedition Magazine;

Writing, seals, and administration

The Indus script, attested by several thousand short inscriptions—often on square stamp seals depicting animals such as the so‑called “unicorn”—remains undeciphered. Approximately 400 distinct signs have been identified; most inscriptions are brief and lack bilinguals, complicating decipherment. Britannica. Script development is traced from earlier potters’ marks and signs appearing in the Early Harappan phases to standardized inscriptions in the Mature period; a large signboard from Dholavira attests to public display of signs. Britannica; UNESCO World Heritage Centre. The remarkable uniformity of weights and measures across the Indus zone suggests regulated metrology underpinning craft production and exchange. Kenoyer (chapter summary, Cambridge University Press).

Society, civic order, and belief

Urban layouts emphasize civic infrastructure—streets, drains, wells, and reservoirs—over monumental palaces or state temples, and domestic architecture ranges from modest multi‑room houses to larger courtyard residences, indicating social differentiation within a shared urban fabric. UNESCO World Heritage Centre; Britannica. Indus material culture includes figurines and seals with animal and anthropomorphic motifs; interpretations of religion remain uncertain, and proposed identifications such as the “Pashupati” (a horned, seated figure on a Mohenjo-daro seal) are debated in scholarship. Britannica; Britannica; Wikipedia summary with sources cited therein for object history.

Environment, landscape change, and urban transformation

Multiproxy geomorphological and archaeological evidence indicates that Indus settlement dynamics were strongly tied to monsoon-fed fluvial systems: intensified monsoon circulation and tamed flooding facilitated urban growth, while subsequent aridification after ~2000 BCE reduced flood intensity and progressively dried monsoon rivers on the interfluve (Ghaggar–Hakra), contributing to dispersal from large cities and an eastward shift toward the upper Indo‑Gangetic plains. Proceedings of the National Academy of Sciences (open access). This framework helps explain repeated flood episodes at Mohenjo-daro and the decline of large urban centers without invoking a single catastrophic event. Britannica; Proceedings of the National Academy of Sciences.

Major sites

• –Harappa: large urban center in the upper Indus region with standardized bricks, weights, and evidence for specialized crafts; its early deposits extend to ca. 3300 BCE. Harappa.com; Kenoyer (chapter summary, Cambridge University Press).
• –Mohenjo-daro: extensive lower-town and citadel complex with the Great Bath, drainage networks, and densely planned housing; inscribed on the UNESCO World Heritage List in 1980. UNESCO World Heritage Centre; Britannica; Britannica.
• –Dholavira: stone-built city with a tiered plan and large reservoirs exemplifying water management; UNESCO inscription 2021. UNESCO World Heritage Centre; The Indian Express.
• –Lothal: fortified town with warehouse, bead-making, and a brick-lined basin identified as a tidal dock; interpretation of the basin as a dock is accepted by ASI/UNESCO but has been questioned in the literature. UNESCO Tentative List; [journal://American Anthropologist|The Harappan "Port" at Lothal: Another View|1968).

Language and population history

The language(s) of the Indus remain unknown; hypotheses (e.g., Dravidian) exist, but the script is undeciphered and inscriptions are short, limiting linguistic inference. Britannica. Ancient DNA studies provide a preliminary genetic window: a 2019 genome from Rakhigarhi (Cell) and contemporaneous “Indus‑periphery” individuals from Iran/Turan (Science) indicate ancestry comprising Iranian-related and South Asian hunter-gatherer lineages, with little to no steppe pastoralist ancestry present during the Mature Harappan period; authors caution that broader sampling is needed. Harvard Medical School summary; ScienceDaily (with journal references).

Natural setting

The civilization took shape along the Indus River and related basins; the river system’s seasonal dynamics were integral to the agricultural base and settlement geography of the region. Britannica.