<p>Traditional Cultural Places (TCPs) are historic properties recognized for their cultural significance. Cultural value is determined by living communities and is not dependent on the presence of human-made or human-modified site features. Although eligible for consideration in federal decision-making, TCPs are often absent from state and federal heritage inventories due to challenges in their identification. Given the relationship between people and place, community-based inventory efforts offer opportunities to both document this heritage and support longer-term relationship building. Using an interdisciplinary methodology, we held participatory place-based mapping workshops in Guam and the Commonwealth of the Northern Mariana Islands to document TCPs and maritime archaeological sites. While ultimately successful, the workshops and our shared experiences were shaped by political tensions in the U.S. Pacific Island territories. This paper shares preliminary results on the use of participatory geographic information systems to inventory heritage, including TCPs. Our experiences, and those of our collaborators, are further contextualized within broader themes of Pacific militarization and critical minerals mining.</p>