OBJECTIVE In this study we assessed the structure and function of local and district health agencies throughout the United States. We compared these findings with those from a previous national assessment done a decade earlier. METHODS We surveyed the state health officers of all 50 states in the summer of 2001 in regard to the structures and functions of their state's local and district health agencies. RESULTS Forty-seven states completed the survey for a 94 percent response rate. Forty-three percent have a regional or district structure in place. According to more than 80 percent of the respondents, local health departments serve all areas of their state. Local boards of health provide guidance and oversight in two thirds of the states. Most local health departments continue to perform a variety of traditional public health functions, as well as a variety of newly emerging responsibilities. Many local functions varied by geographic regions, population size, and organizational type. CONCLUSIONS The study identified structural and functional changes in the local and district health agencies of state public health systems over the last decade. The stage is set for future work on the relationship between public health structure and function, and performance in the 21st century.