The use of a measure of geographic proximity to help explain enrollment competition among postsecondary institutions was investigated. The measure, the number of miles between institutions, was obtained by determining the longitude and latitude coordinates for about 99% of the schools in the Higher Education General Information System universe. Differences in the average distance between a focal institution and its competitors were examined based on variations in institutional characteristics (e.g., control, enrollment size, selectivity, type, program emphasis, and region). The names of competing institutions were obtained from responses to a previous study of colleges and universities. Findings support the view that enrollment competition is primarily a local affair and that enrollment markets are highly segmented geographically. Private institutions had the greatest average distance followed by religious institutions. Additional findings concerning distance and the variables of control, size, selectivity, program emphasis, and region are presented and tabulated. A 74-page alphabetical list of higher education institutions by state provides the following information for each school: FICE code, county, and latitude and longitude coordinates. (SW)