Following a high-quality early care and pre-K experience, the kindergarten-through-third-grade years set the foundation upon which future learning builds; and strengthening this continuum creates opportunities for later success. Key components of a quality experience in K-3 include school readiness and transitions, kindergarten requirements, educator quality, prevention, intervention and assessments, and social and emotional learning and mental health. Education Commission of the States researched the policies and regulations that guide these key components in all 50 states to provide this resource and many others. The data in this document show that: (1) at least 13 states plus Washington, D.C., have principal credentials that cover the preschool through grade 12 span; (2) an additional five states include multiple principal credentials that may include birth through grade three, preschool through grade three and kindergarten through grade six; (3) six states have credentials specific to the elementary grades, generally kindergarten through grade six; and (4) twenty-five states have no statute, rules or regulations specific to this issue.