Administrative data refers to information about individual children, families, and/or service providers that is collected and maintained as a part of program operations. Research using early care and education (ECE)-related administrative data has often focused on child care subsidy policies, use of ECE programs, access to ECE programs, and other topics. The purpose of this brief is to highlight a range of federal, state, and local administrative data sources that could be used to address policy-relevant ECE questions. It describes data sources across four main areas: (1) early care and education; (2) health; (3) child welfare, public assistance, and human services; and (4) employment. It offers examples of the types of ECE research questions that could be answered when data sources from these areas are linked with other sources (e.g., when various ECE data sources are linked with one another, as well as when ECE data are linked with other data). The brief serves as a starting place for researchers or state agency staff interested in understanding the variety of administrative data that could be linked together to answer policy-relevant questions in early care and education.