Excavations at Ashdod‐Yam exposed a fortification system that features a massive mudbrick wall with large earthen ramparts laid on either side. This fortified horseshoe‐shaped enclosure once surrounded what was likely a human‐made harbor and an adjacent acropolis with complex earthen architecture, constructed and active during Iron Age IIB–C (eighth–seventh centuries B.C.E.). These Iron Age public structures are at the center of the current research. In this paper, we present the geoarchaeological analyses of Ashdod‐Yam's earthen architecture. We applied a multidisciplinary methodology to new evidence for mudbrick manufacture with the goal of understanding the relationship between governing bodies and craftsmen. The analyses combine X‐ray fluorescence, loss on ignition, environmental scanning electron microscopy, and thin‐section petrography to investigate raw material procurement, manufacturing choices, and labor organization at Ashdod‐Yam during Iron IIB–C. Construction techniques and the standardization of the mudbrick recipe point to a local enterprise regarding the site's public earthen architecture. Furthermore, the degree of labor organization must have been closely observed and supervised by a central political power. Thus, it is argued here that construction and maintenance of the site was carried out by the kingdom of Ashdod, either as a part of its own local initiative or on behalf of the Neo‐Assyrian empire.