Since the COVID-19 pandemic emerged in the United States in March 2020, districts across the nation have faced the difficult task of reopening schools safely and keeping them open. It is useful to learn from the successes of districts that have used multilayered mitigation strategies to reduce the risk of in-school transmission. This brief describes reopening efforts in San Diego County, CA, where 98% of districts had reopened for in-person learning as of May 2021. The San Diego County Office of Education has mobilized technical assistance, leveraged partnerships, and gathered data to support districts as they have navigated initial school closure, distance learning, and planning for reopening. The brief also describes how the county supported the reopening of child care programs and highlights the reopening strategies adopted by Cajon Valley Union School District, the largest district in the county to resume in-person learning in fall 2020. It is part of a series of reopening profiles produced by the Learning Policy Institute to disseminate key public health research and reopening strategies to educators and policymakers.