Studies of ancient Mesopotamian cities have long focused on their institutions. Here, instead, the authors draw on recent investigations at the third-millennium BC site of Lagash (modern Tell al-Hiba, Iraq) to explore urban density, economy and sustainability at one of the largest ancient urban centres of the region. Drawing on excavation, environmental and remote-sensing data, the authors adopt a multi-scalar approach, revealing dense urban occupation, with subdivision into distinct walled quarters, as well as evidence for multiple foci of intensive industrial production and the exploitation of a rich mosaic of surrounding micro-environments. The study emphasises how a combination of new field data and alternative research directions offers novel insights into early urbanism.