Setting <p>The Middlesex-London Health Unit (MLHU) is a local public health agency serving a population of 500,000 people in southwestern Ontario.</p> Intervention <p>Public health can have a nearly infinite scope. Given the impact of our social, economic, and physical environments on health, everything can rightly be considered a “public health issue.” However, the role of a local public health agency in addressing a “public health issue” varies widely and is not always clearly described.</p> <p>We have described and defined the interventions of a local public health agency and have developed a classification of common interventions. These interventions outline the work that we do for the community, clearly and concretely articulating the actions we take to protect and promote health.</p> Outcomes <p>The work of local public health agencies can be categorized and classified by these common interventions:</p> <p>• Communication and social marketing</p> <p>• Education and skill building</p> <p>• Healthy public policy development</p> <p>• Community and partner mobilization</p> <p>• Surveillance</p> <p>• Inspections</p> <p>• Investigations</p> <p>• Case, contact, and outbreak management</p> <p>• Clinical services delivery</p> <p>• Health resource inventory management</p> <p>• Vector control</p> Implications <p>The benefits of defining the interventions of a local public health agency include an improved understanding of the skills required to do the work; opportunities to strategically target prioritized public health issues, utilizing the full suite of interventions to maximize impact; the ability to adapt to changing priorities; opportunities to effectively measure organizational performance; clarity with partners regarding roles and responsibilities in addressing public health issues; and an enhanced ability to tell others what we do and demonstrate our value.</p>