As part of its evaluation of the Illinois State Board of Education's Preschool Development Birth through Five Planning Grant (PDG B-5), Illinois Workforce and Education Research Collaborative (IWERC) completed an overview and evaluation of strengths and weaknesses in the current early childhood data systems. To complete this review, IWERC examined the data available for programs housed at various state agencies, data housed or available through intermediaries, information collected from the activity leaders on the PDG B-5 grant on data quality, availability, and utility, questions and comments about data asked by internal and external stakeholders during its own execution of PDG B-5 grant activities, and discussion of issues raised throughout this process. This report discusses the statewide data sets and systems related to four broad areas: (1) Programs in early childhood; (2) Program Quality; (3) Teachers/Staff in early childhood programs; and (4) Student Experiences and Outcomes in early childhood programs. This review might support state agencies in improving data quality, availability, connectivity, and utility for agency staff, key stakeholders, and the general public, along with supporting the transition of data to the new early childhood agency, the Illinois Department of Early Childhood (IDEC), as the Transition Advisory Committee considers data as a key issue (particularly the Data, Analytics, and Insights work group).