Colleges and universities increasingly voice a concern for, and dedicate institutional attention to ethnic "diversity" within their student population, a trend that aligns with broader concerns about social (in-)equity in US Elementary and Secondary schools. Current operational definition of diversity focuses on demographic variety of student population in particular, race/ethnicity as the major indicator of student diversity. This study used a measure of ethnic diversity, the Generalized Variance (GV) approach to investigate the diversity of students enrolled in twenty California State University (CSU) campuses. CSU system-wide diversity index was calculated and used as a target to determine the proximity of the campuses to the system-wide target. The results of analysis of fall 2011 student enrollments of CSU system show that the 1st year enrollees on the campuses were not significantly diverse than the "Other" students (sophomores to graduates) on the campuses. However the degree of diversity of 1st year and "Other" students on the same campuses showed some discrepancies or mismatches, i.e., there were some campuses with ethnically diverse 1st year students and less diverse "Other" students or vise versa. Most of the CSU campuses fell below the system-wide diversity index. Only 30% or six campuses were more ethnically diverse than the system-wide student population. The data seem to indicate that for CSU campuses, locale is one of the important factors that determine the ethnic diversity on the campuses.