What is public health? Defining public health is the first step before engaging in a search for the history of public health. Research the history of public health in your region, state, borough, parish, or locality and then describe how public health strategies and responses have changed over time (for my area please use the St. Louis, Missouri area for research since I am close to that area). You may select any public health information during the time frame from 1950 -1785. Depending upon your location, you may be able to find a significant amount of public health nursing and sanitation history.