This landscape analysis seeks to identify the “who” and “where” of United States in situ global ocean carbon observing, analyzing where gaps in these efforts remain. Aircraft and satellites collecting atmospheric carbon measurements (and other parameters necessary for carbon flux calculations) were not included in this analysis focused on in situ observations. This study was used to inform OAR Ocean Carbon Observing Science Plan Goal 1 research questions, objectives, and suggested actions which addresses filling observational and knowledge gaps (Kelly et al. 2025).