The Early Learning Challenge (ELC) program awarded more than $1 billion in four-year grants to 20 States to implement comprehensive and cohesive high-quality early learning systems that support young children with high needs and their families. A key lever in making these improvements was the enhancement of States' Quality Rating and Improvement Systems (QRIS). A QRIS is designed to measure, rate, and dissemination information about the quality of the early learning and development programs that participate in the QRIS. Through ELC, States worked across agencies to improve, or in some cases, reinvent their QRIS. This report summarizes the progress ELC States made since the program began in 2012. It includes selected examples of key initiatives States undertook to create a comprehensive system of high-quality programs for young children and their families. Specifically, it looks at States' efforts to refine their QRIS; examine progress elements (including early learning standards, screenings, and assessment systems); engage and support families; support the early learning workforce; enhance early childhood data systems; and foster community connections. The content was drawn from States' ELC Annual and Final Performance Reports. As a result of the efforts States have undertaken, it can now be said that more children with high needs are enrolled in high-quality programs and more programs participate in the States' QRIS. States made progress in developing and strengthening their comprehensive early learning and development systems. States used the ELC program to make advancements and drive positive changes in their early learning and development systems, often in the face of significant challenges. Other States are benefiting from these experiences and lessons as they work on improving their own systems.