This report summarizes publicly available information about the coordination or inclusion of Head Start across various aspects of state and territory ECE systems. The findings are organized by nine topics: the agency housing Head Start Collaboration Offices, Head Start grants and enrollment, state Head Start spending, Quality Rating and Improvement Systems (QRIS), state pre-K, child care subsidy policies, Early Head Start-Child Care Partnerships, Head Start grant-level partnerships, and integrated data systems. The report also addresses ways in which future research could help the field better understand these connections between Head Start and state or territory ECE systems. (author abstract)