Purpose: This study evaluated the validity and utility of the Local Public Health System Assessment Instrument (Local Instrument) of the National Public Health Performance Standards Program in rural settings. Methods: The study compared the Local Instrument scores of 6 rural local public health systems to external assessments of those public health systems. The 6 public health systems represented 3 states in which 1 of the 2 local jurisdictions had scored well below and the other well above the state median in a pilot test of the Local Instrument. The study design featured a case study approach consisting of an iterative and integrated combination of semistructured individual and focus group interviews along with the collection of archival materials provided by the 6 public health systems. Findings: Despite differences in Local Instrument scores, the representative public health systems in each state provided roughly the same levels of public health services. Sites varied tremendously in the percentage of survey items rated highly or less relevant. Conclusions: The National Public Health Performance Standards Program Local Instrument can provide a useful structure and process for assessing public health system performance at the local level. Key informants provided several recommendations to improve the Local Instrument, including clarification of difficult terminology and acronyms, and development of multiple instruments structured around subsets of survey items.