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 comprehensive resource and many others. The data in this document show at least 35 states plus Washington, D.C., have multiple credentials for various grade spans covering the early years and grades. The most common are birth through grade three, preschool through grade three and elementary/kindergarten through grade six; several also include special education. Additionally, five states specify only a birth through grade three credential, along with four that specify only a preschool through grade three credential. Several other credentials exist but are less frequent.