The Traffic Injury Research Foundation USA, Inc. (TIRF USA) in partnership with the Association of Ignition Interlock Program Administrators (AIIPA), and TIRF Canada released Ignition Interlock Installations: 2020 State Data. This study is based on US interlock installation data collected from state agencies in 2020. This report presents a comprehensive picture of interlock installations across the country and provides state agencies and impaired driving stakeholders with a benchmark to measure annual usage and growth in interlock programs. These data provide a comprehensive picture of interlock installations across the United States and are a useful benchmark for state ignition interlock program administrators and the impaired driving community to measure interlock program participation.