Castles are iconic monuments in the landscape from the Middle Ages, a period which shaped the cultural geography of modern Europe. The buried archaeology provides an important lens through which to examine important phases in the political history of these monuments, such as the establishment of castles, hiatuses in their use or function, and abandonment. This project uses geoarchaeological data to inform and drive pan-European heritage research and management strategies at medieval castles and castle sites. Geoarchaeology applies earth science techniques to understand archaeological stratigraphy at the microscopic scale. It is applied here to the buried archaeology at castle sites, which can be often overlooked in conservation and management plans in favour of any standing remains. This research highlights the potential threats to the buried archaeology by understanding the different burial environments and the effects that conservation and renovation work have on the preservation of buried sediments and materials.