|In the U.S., low-income, uninsured women have used mammography less frequently and have experienced higher breast cancer mortality rates than their wealthier and insured counterparts (Harper et al., 2009; National Center for Health Statistics, 2013). These discrepancies are problematic because low-income, uninsured women often rely on community resources, such as free screening programs, to obtain healthcare services (Daniels, 2008; Link & Phelan, 1995; Lynch & Kaplan, 2000). Although researchers have investigated person- and area-level factors that may influence mammography use in the general U.S. population, little research to-date has examined how socioeconomic characteristics of communities, which represent shared exposures of all who live there, may affect mammography use among low-income, uninsured women (Pruitt, Shim, Mullen, Vernon, & Amick, 2009; Schueler, Chu, & Smith-Bindman, 2008). Moreover, despite policy attempts to increase access to mammography services, low-income, uninsured women remain at risk for not receiving timely mammograms, particularly in states not expanding Medicaid such as Kansas (Howard et al., 2015; Kaiser Family Foundation, 2013). Therefore, the purpose of this dissertation was to explore the relationship of county-level socioeconomic characteristics and mammography use by low-income, uninsured women in Kansas. Using a combination of multiple linear regression analyses and hierarchical generalized linear models (HGLM), three related studies analyzed the association of county-level socioeconomic characteristics and mammography use among women who participated in a free screening program in Kansas, known as Early Detection Works (EDW), from 2009-2014. These studies found that county-level uninsurance and socioeconomic deprivation were significantly associated with mammography use, such that counties with higher levels of uninsurance and lower levels of socioeconomic deprivation exhibited higher mammography use in the EDW program. These results suggest that even when mammography screenings were free, characteristics of the broader environment may have influenced their utilization. Moreover, the EDW program may have been acting as a ‘pseudo insurer’ by converting uninsured women into patients with contracted payments for mammogram services. Collectively, these findings imply that research and policy efforts to expand health insurance may extend comprehensive coverage to previously uninsured low-income women and free-up limited EDW resources to target other women in need of mammography services.