Background: Health disparities persist among morbidity and mortality rates in the United States. Contributing significantly to these disparities are the ability to pay for health care (largely, access to health insurance) and access to, and capacity of, the primary care health workforce. Purpose: This article examines key determinants of health (DOH) including demographics, public and regulatory policies, health workforce capacity, and primary health outcomes of four states of the United States. The context of this study is the potential association among health care disparities and myriad DOH, among them, the restrictive nurse practitioner (NP) scope of practice (SOP) regulatory environment, which are documented to influence access to care and health outcomes. Methods: This descriptive study explores current NP SOP regulations, access to primary care, and health outcomes of key chronic disease indicators diabetes, hypertension, and obesity in Alabama, Colorado, Mississippi, and Utah. These states represent both the greatest disparity in chronic disease health outcomes (obesity, diabetes, and hypertension) and the greatest difference in modernization of their NP SOP laws. The Affordable Care Act has greatly expanded access to health care. However, it is estimated that 23 million Americans, 7% of its total population, will remain uninsured by 2019. Discussion: Restrictive and inconsistent NP SOP policies may continue to contribute to health workforce capacity and population health disparities across the country, with particular concern for primary care indicators. The study findings bring into question whether states with more restrictive NP SOP regulations impact access to primary care, which may in turn influence population health outcomes. These findings suggest the need for further research. NPs are essential for meeting the increasing demands of primary care in the United States, and quality-of-care indicator research supports their use.