The 2017–18 National Postsecondary Student Aid Study, Administrative Collection (NPSAS:18-AC) restricted-use data file contains administrative record data on student financial aid, enrollment, demographic characteristics, institution characteristics, and income for approximately 245,000 undergraduate students and 21,000 graduate students attending 1,900 postsecondary institutions in the 50 states, the District of Columbia, and Puerto Rico. Data on undergraduate students are nationally representative, as well as state-representative for 30 states overall, 36 states for public 2-year institutions, and 45 states for public 4-year institutions. NPSAS covers topics pertaining to student enrollment with a focus on how individuals and families finance postsecondary education. NPSAS:18-AC is based solely on data collected from administrative data sources and, unlike other NPSAS studies, does not include student survey data.