Over the first two full school years under the COVID-19 pandemic, K-12 enrollment in public schools fell dramatically (i.e., by more than 1.2 million students) with losses concentrated among the youngest students. Currently, little is known about where these students went and what learning environments they are experiencing. In this research note, I present leading descriptive evidence on this question by combining public-school enrollment data with newly collected state-level data on private-school and homeschool enrollment and Census-based estimates of the changed size of the school-age population resident in each state. These data indicate that, between the 2019-20 and the 2021-22 school years, homeschool and private-school enrollment grew by 30 and 4 percent, respectively. Across the states with available data, increased homeschool enrollment and population loss each explain 26 percent of the public-school enrollment decline while the more modest increase in private-school enrollment explains 14 percent. Over a third of public-school enrollment loss cannot be explained by observed changes in nonpublic-school enrollment and the school-age population. This large residual indicates the pandemic may have shaped learning opportunities, particularly for the youngest children, in additional ways (e.g., skipping kindergarten, unregistered homeschooling, truancy) that merit further scrutiny.