The Community Eligibility Provision (CEP) of the National School Lunch Program allows high-poverty schools to provide USDA school meals at no charge to all of their students. USDA reimbursement for meals is simplified by making use of routinely collected administrative data, such as participation in the Supplemental Nutrition Assistance Program (SNAP, formerly food stamps) or Temporary Assistance for Needy Families (TANF), rather than collecting school meal applications. Schools and districts with at least 40 percent of enrolled students identified as participating in these assistance programs through the administrative data--also known as the Identified Student Percentage, or ISP--are eligible to participate in the CEP. This report examines the characteristics of school districts that participated in the CEP in school year 2015-16--with participation defined as CEP being implemented in at least one eligible school in the district--using administrative data from USDA's Food and Nutrition Service, the National Center for Education Statistics, and State education agencies, where available. The highest school-level ISP in the district was found to be significantly associated with CEP participation, holding other factors constant, although the association varied for different sized districts. Participation also varied significantly by region and length of time since CEP became available.