Teachers are critical to student learning, but adequately staffing classrooms has been challenging in many parts of the country. Though teacher shortages are widely reported, they are poorly understood, particularly in terms of the magnitude and variation of the shortages, and reported figures are often localized and anecdotal. To address this gap, we systematically examine news reports, Department of Education data, and publicly available information on teacher shortages for every U.S. state. We characterize the data landscape and find there are at least 39,700 vacant positions along with at least 288,000 positions being held by underqualified teachers, both of which are conservative estimates of the extent of teacher shortages nationally. We discuss the implications of our findings for improving data systems, including more specific and consistent reporting of shortage, as well as implications for teacher preparation and education policy.