The Bureau of Radiological Health, U.S. Public Health Service, provides comprehensive off-site radiological safety and medical programs for underground nuclear tests at the Nevada Test Site and for nuclear tests and experiments conducted at other geographical sites for non-weapons research and peaceful purposes. The specific physical requirements for these latter categories of use may preclude their being conducted at the Nevada Test Site. Future underground nuclear detonations for research and peaceful purposes may be held in locations which are not necessarily remote from relatively sizeable civilian populations. It is thus desirable to delineate the particular problems and their management involved in the public health medical planning for population safety, including such aspects as evacuation. These medical planning and management activities and their implementation for Project Sterling, a 350-ton yield underground nuclear detonation, which was conducted for seismic research purposes on 3 December 1966, in the Tatum Salt Dome near Hattiesburg, Mississippi, are described. (Author)