Tactical locations, military ports and airports which are of such importance that they must be retained or controlled for the purposes of national defense are called key points. Key points, together with their surrounding areas including any body of water, are defined as a vital area.

The boundary of a vital area is defined by outlining the outermost points of any military base or installation as a baseline perimeter, and includes any surrounding area bounded by a specified range of distances.

Unless otherwise specified, land areas and territorial waters within the vital area are classified as either Zone One or Zone Two. Airspace within vital areas is classified as either a No-Flight Zone or a Restricted Flight Zone. Depending on its geographic, transportational as well as local residential considerations, the specifications of the above regions are defined as follows:
Subparagraph 1 The area within a radius of approximately four to six hundred meters from the baseline perimeter is defined as Zone One.
Subparagraph 2 Within the range of approximately three to four thousand meters surrounding the area of Zone One is defined as Zone Two.
Subparagraph 3 The airspace within which no aircraft is permitted is defined as a No-Flight Zone. The airspace within which only permitted flights are allowed is defined as a Restricted Flight Zone. The rules and restrictions of the above two zones are to be specified by the Department of Defense, if necessary, accompanied by topographic maps illustrating a detailed outline of the stated area.
The above stated zones as they apply to military ports, strategically important ports, naval defense facilities, airports, air force defense facilities and any defense related areas are to be defined and posted by the Department of Defense.