Project Summary Up to 3 billion people will reside outside of the human climate niche due to climate change by the end of the century and the wholesale abandonment of communities are now a reality. As some communities in the US become increasingly environmentally precarious and settlements become abandoned, migration away from these areas could increase exposure to displacement-related stressful life events (DR-SLEs) and their impact on health. Such DR-SLEs are associated with short-term reduced health outcomes but little is known about how these short-term reduced health outcomes could translate into long-term reduced health outcomes. No database of US abandoned settlements currently exists, hindering our ability to study the long-term health impacts of DR-SLEs. This project will build a comprehensive database of all enumerated places since 1890 and verify any settlements abandoned during since. We will then leverage this database by linking verified, abandoned places between Census 1940 and 1950 to individuals in CenSoc, an NIA-funded database which matches deceased persons in the Social Security Administration’s Death File to their 1940 Census record, to estimate the causal effect of settlement abandonment on longevity using a synthetic control design. Findings from this project will directly inform ongoing federal, state, and local policies of managed retreat and illustrate the mortality penalty settlement abandonment could place on the millions of anticipated US-based climate migrants this century.