The proposed supplement consists of five innovative pilot projects to be added to the R24 Network on Life Course Health Dynamics and Disparities in 21st Century America (NLCHDD). All five projects are population-based social science research that address NIA?s announced priorities in the area of Alzheimer?s disease and related dementias (ADRD) research. In addition, all five directly advance the overarching objective and specific aims of the parent grant. The overarching objective of the NLCHDD is to create a network of emerging, established, and underrepresented life course and aging researchers across multiple disciplines to generate new evidence and disseminate data and analytic resources to better understand the worrisome trends and disparities in U.S. adult health and longevity across the life course and in geographic context. To achieve this objective, the NLCHDD stimulates innovative and interdisciplinary research to generate this evidence through multiple activities, including supporting innovative pilot projects. The five proposed supplemental pilot projects are: (1) Education, Psychological Resilience, and Cognitive Decline in Later Life will examine the potential role that psychological resilience plays in mediating and mitigating the association between educational attainment and cognitive decline, (2) Neighborhood Adversity and Cognitive Decline and Dementia Among US Older Adults will examine how long-term exposure to neighborhood adversity impacts cognitive decline and dementia in older ages, and how physiological dysregulation may mediate the association and how psychosocial resources could mitigate the association, (3) Alzheimer?s Disease and Related Dementias across the Rural-Urban Continuum will examine how ADRD develops over time and across the urban-rural continuum, and how these patterns differ across region of residence and subgroups defined by gender, race/ethnicity, and education, (4) Effects of Air- based Chemical Toxicants on Cognitive Function and Impairment Among Older Adults will link estimates of exposure to chemical air pollutants to respondents in the HRS HCAP subsample and investigate the synergistic effects of exposure to air pollution and social stressors on race/ethnic disparities in cognitive functioning, and (5) Fitting the Geographic Distribution of Alzheimer?s Disease and Related Dementias to Administrative Divisions for Health Policy Effectiveness: A Modifiable Areal Unit Problem Approach will integrate data from multiple sources to estimate variation in ADRD across various levels of geography to understand how different spatial units may obscure accurate representation of geographic variation in ADRD. These projects will produce important findings about the development of and disparities in ADRD.