This study examined demographic and geographic variability in aggregated school-level data on the percentage of students achieving the FITNESSGRAM[R] Healthy Fitness Zones[TM] (HFZ). Three-way analyses of variance were used to examine differences in fitness achievement rates among schools that had distinct diversity and socioeconomic status profiles. The results revealed age-related declines in the percentage of youth who achieved the HFZ standard for cardiovascular fitness (elementary school: 70%; middle school: 46%; high school: 34%). Interestingly, there was little evidence of age-related declines in other fitness dimensions. School-level attainment of fitness was consistently higher in schools categorized as low diversity and high socioeconomic status. Clear spatial patterns in fitness achievement were also evident when data were analyzed at the region and county level using geodemographic information system software. (Contains 3 tables, 2 notes, and 4 figures.)