Li ZR, Xie E, Crawford FW, et al. - In view of the observation that in the United States, opioid-related overdose has become one of the most common causes of death, researchers here performed a spatiotemporal analysis of the locations of reported heroin-related incidents linked with EMS dispatches in the city of Cincinnati, Ohio. The spatial and temporal variability were investigated as a function of economic and demographic covariates, accessibility of medical facilities, and features of the built environment. Using publicly available data on suspected heroin-related emergency calls (n = 6,246) from August 1, 2015, to January 30, 2019, they identified higher numbers of heroin-related incidents in correlation to features of the built environment, including the proportion of parks (relative risk [RR] = 2.233), commercial (RR = 13.200), manufacturing (RR = 4.775), and downtown development zones (RR = 11.362). Further, there was a positive correlation of the number of suspected heroin-related emergency calls with the proportion of male population, the population aged 35–49 years, and distance to pharmacies and a negative correlation with the proportion aged 18–24 years, the proportion of the population with a bachelor's degree or higher, median household income, the number of fast-food restaurants, distance to hospitals, and distance to opioid treatment programs. After adjusting for covariates, there remained significant spatial and temporal heterogeneity in the risks of incidents.