Even as concerns about nursing shortages continue nationwide and for individual states in the United States, there is little information on the impact of nursing shortages at substate levels, such as counties or groups of small counties. National and state level assessments can mask wide geographic variation in the distribution of registered nurses (RNs). The Center for Health Workforce Studies at the School of Public Health, University at Albany, developed a practical approach to projecting RN supply and demand at substate levels. The experimental model used in this research was adapted from a methodology utilized for the RN National Supply Model and National Demand Model developed by the Health Resources and Services Administration in the department of Health and Human Services to make RN supply and demand projections at the broader national and state levels. The Center's research highlighted the value of substate analyses in the identification of RN supply and demand gaps and found that supply and demand gaps vary greatly by region and within regions. This study also provided an in-depth understanding of the dynamics that drive substate labor markets for RNs as well as the need for substate analyses to help policymakers better allocate scarce resources to address nursing shortages.