Objective: The objective of this study was to examine the association of patient- and county-level factors with the emergency department (ED) visits among adult fee-for-service (FFS) Medicaid beneficiaries residing in Maryland, Ohio, and West Virginia. Methods: A cross-sectional design using retrospective observational data was implemented. Patient-level data were obtained from 2010 Medicaid Analytic eXtract files. Information on county-level health-care resources was obtained from the Area Health Resource file and County Health Rankings file. Results: In adjusted analyses, the following patient-level factors were associated with higher number of ED visits: African Americans (incidence rate ratios IRR = 1.47), Hispanics (IRR = 1.63), polypharmacy (IRR = 1.89), and tobacco use (IRR = 2.23). Patients with complex chronic illness had a higher number of ED visits (IRR = 3.33). The county-level factors associated with ED visits were unemployment rate (IRR = 0.94) and number of urgent care clinics (IRR = 0.96). Conclusion: Patients with complex healthcare needs had a higher number of ED visits as compared to those without complex healthcare needs. The study results provide important baseline context for future policy analysis studies around Medicaid expansion options.