Background: Social support, including emotional, instrumental, and informational forms, is a critical social determinant of health in later life, and adequate emotional support is tightly linked to higher self-rated health in U.S. older adults. However, in rural communities, accessing social support is particularly challenging due to structural barriers, including transportation, provider, and telecommunications infrastructure shortages. Objective: This scoping review aims to map and characterize barriers to access to social support among community-dwelling older adults in rural and urban areas in the United States and identify research gaps to inform policy and practice. Methods: The review is based on the PRISMA-ScR guidelines. A search was conducted on MEDLINE/PubMed, CINAHL, PsycINFO, SocINDEX, AgeLine, Web of Science, and Scopus, as well as relevant U.S. agency and gray literature sources. Eligible studies included quantitative, qualitative, and mixed-methods designs reporting on barriers to emotional, instrumental, or informational support measured among adults aged at least 60 years after 1990 and published in English. Barriers will be organized using five supply-side domains: approachability, availability/accommodation, affordability, acceptability, and appropriateness. Expected outcomes: Preliminary synthesis suggested that rural barriers are mostly supply-side structural transportation, workforce, and broadband, whereas urban barriers are more commonly demand-side fragmentation, eligibility bottlenecks, and cultural mismatches. Research gaps include inconsistent rural/urban definitions, underrepresentation of minority elders, and lack of distinction between structural and functional support measures. Conclusion: Tackling rural supply-side barriers is crucial for attaining just aging in place and realizing geographic disparities in the health-related benefits of ample social support.