This article uses data from the National Public Health Performance Standards Program to explore how the performance of essential public health services varies across communities and to identify underlying domains of activity that appear to drive variation in performance. Cross-sectional data were used from 315 local public health jurisdictions located within seven states that participated in the Performance Standards Program pilot tests between 1999 and 2001. Results demonstrate that local public health systems vary considerably in the extent to which they perform essential services and meet established performance standards. Factor analysis results indicate that four underlying domains of activity explain much of the variation observed in the individual performance measures, and that achieving performance standards for a single essential public health service often involves more than one underlying domain of activity. The findings suggest that composite measures constructed from the Performance Standards Program can assist public health decision makers in monitoring the performance of public health systems and identifying promising pathways for improving performance.