Early evidence indicates that the COVID-19 pandemic sharply reduced public school enrollment in many states. However, little is known about the underlying patterns of these declines. Using new district-level data from Massachusetts, we find that these declines were concentrated in traditional districts while charter, virtual, and vocational districts "increased" their enrollment. Though the enrollment declines in traditional districts were widespread, we also find that the percent declines were significantly larger in smaller districts and those serving higher concentrations of White and economically disadvantaged students. The implications for understanding the pandemic's effects on learning opportunities and the anticipated fiscal stress on public schools are discussed.