Despite a resurgence in Scottish fort studies, few sites have been investigated, and fewer still at the scale reported in this volume. Over 2014-17, Perth and Kinross Heritage Trust, working with AOC Archaeology Group, excavated three hilltop forts on the Tay estuary to explore both their enclosing works and internal buildings, and uncovered an impressive assemblage of small finds. At Moredun fort on Moncreiffe Hill, a previously unknown monumental roundhouse, a rare La Tene bird-head brooch, and evidence of shale bangle industry were uncovered. At Castle Law, Abernethy, excavated in the 1890s and the type-site of Childe's 'Abernethy complex', re-excavation prompted reassessment of the artefacts from original excavations to reveal new evidence of the deposition of artefacts and animal bones within its cistern. Excavation of the enclosing works of these sites, and Moncreiffe fort, suggest an evolution of fort defences from simple earth and stone ramparts to massive timber-laced walls - the murus Gallicus described by Caesar - reflecting high status sites with restricted access for a social elite. Hillforts of The Tay was part of the Tay Landscape Partnership Scheme, a community heritage initiative and the results of this citizen science project make a significant contribution to establishing Tayside as a well-studied area for the site type both within Scotland, and further afield.