NCHEMS (National Center for Higher Education Management Systems) has worked with the National Association of Systems heads (NASH)--with support from the Lumina Foundation for Education--to develop (1) empirically-based access regions for postsecondary institutions based on student enrollment patterns and (2) access, transition, and completion measures to gauge how well institutions serve their regions with respect to racial/ethnic equity. This work was conducted to provide additional information to the existing comparative college graduation rates by institution and race/ethnicity presented on the website www.collegeresults.org--developed by the Education Trust. From a combination of detailed student enrollment data provided by several states (by county of student residency), state-to-state student migration data provided by the National Center for Education Statistics (NCES), and additional data from NCES, the authors developed the following categories of four-year postsecondary institutions: (1) National Institutions; (2) Statewide Institutions; (3) Multi-State Institutions; (4) Urban Institutions; and (5) Regional Institutions. Graphs and charts are appended. (Contains 7 figures and 7 data sources.) [This paper is submitted to the National Association of System Heads.]