This study examines ecological influences on adult obesity prevalence in the coterminous United States. Several secondary data sources are used in this study to construct a rich dataset of county-level demographic, socioeconomic, and environmental variables. This study uses a spatially explicit approach by using traditional regression methods (i.e., ordinary least squared regression (OLS)), along with geographic weighted regression (GWR) to explore non-stationarity in the relationships between obesity and selected covariates. OLS results reveal that there is a positive relationship between adult obesity and poverty, black residents, Native American residents, and adult physical inactivity at the county level. There is a negative relationship between the percentage of residents who are rural, Hispanic, and college educated. Furthermore, GWR results confirm that place matters and the relationship between ecological influences and obesity prevalence varies substantially across place. GWR provides an empirical basis to design interventions that effectively target obesity at a more local level. © 2014 Springer Science+Business Media Dordrecht.