Abstract Traumatic injury, defined as sudden and severe physical injury, is a leading cause of death and years of life lost in the United States. Regional trauma systems, in which emergency medical providers and acute care facilities integrate and coordinate triage and treatment of injured patients, are broadly implemented in the U.S. and proven to reduce mortality through consolidated, specialized care at trauma centers. Limited access to trauma centers is an important contributor to greater trauma mortality among people living in rural communities. Despite efforts of regional trauma systems to ensure timely, high-quality care for all patients, disparities in trauma mortality by rurality, race, ethnicity, and socioeconomic remain widespread. There is an immediate need to understand the causes of trauma-related disparities across diverse rural and other underserved populations. We propose systems science is needed to understand the causal mechanisms of trauma-related disparities and identify high-impact interventions for rural and other underserved populations. Our long-term research goal is to use complex systems theory and simulation modeling to design, implement, and evaluate system-level changes to regionalized trauma care that improve population health and address health disparities. System dynamics is an established modeling approach for complex, dynamic systems with multiple cause-effect relationships and feedback loops. In this National Institute on Minority Health and Health Disparities (NIMHD) R21 proposal, our short-term objective is to develop a causal loop diagram of regional trauma systems informed by secondary analysis of existing data and key stakeholder input. We will create a comprehensive dataset linking existing statewide data from North Carolina on EMS and in-hospital trauma care, trauma patient mortality, and patient and community demographics and socioeconomic status. To complement these quantitative data, we will engage regional trauma system stakeholders and subject matter experts with qualitative system dynamics methods. Our specific aims are to: (1) evaluate rural, racial-ethnic, and socioeconomic disparities in trauma triage and long-term mortality among North Carolina trauma patients; and (2) create a causal loop diagram for a regional trauma system in North Carolina through stakeholder engagement to identify potential high-impact interventions to address trauma disparities. Upon successful completion of these aims, we will have produced essential preliminary data on trauma-related disparities in rural and other subgroups to pursue system dynamics research to understand and improve population health and quality of care for underserved populations. The proposed research and our long-term research goal has potential for significant scientific impact on health systems modeling that can directly contribute to improving outcomes for patients experiencing acute, life-threatening illness and injury.