To develop statewide estimates of known victims and individuals at risk of human trafficking in Ohio. We collected information from 12 state and local sources including child welfare, legal services, and law enforcement data. We collected the data from agency records dating 2013 to 2018. However, the majority of data were from calendar years 2014, 2015, and 2016 (roughly 95% across individual and aggregate sources). We used probabilistic matching to estimate victim and at-risk cases-accounting for duplicates. According to available data, there were 1032 known victims during the study time frame. We identified approximately 4209 at-risk individuals based on youths presenting with common risk factors for trafficking victimization. Estimating the prevalence of human trafficking is an important public health research priority. As the first "cataloging" of existing record systems in Ohio to our knowledge, this study provided a comprehensive overview of the number of victims and the type of information that is available in the state. This study highlights the importance of moving toward the use of epidemiological approaches to measure the prevalence of human trafficking.