The origins of ancient states is an important archaeological research topic that illuminates the precursors of modern nations. Public buildings, as is the case today, created urban settings in which political, administrative and religious functions were undertaken. This investigation of the ancient Mesoamerican kingdom of Izapa reveals a network of urban centres laid out according to shared design principles. While the capital city of Izapa has long been known, the authors’ research reveals, for the first time, the entire Izapa kingdom. This work provides an important new insight into the origins of political hierarchy and urban life in pre-Hispanic Mesoamerica.