Tyranny of Dragons
The Savage Frontier is the name given to the unsettled and sparsely settled areas in The North, not including major cities, towns, and any settlements in their immediate spheres of influence. In the vernacular, It is a term used to describe the "other" or to imply the "uncivilized" areas of danger, risk and the untamed.
The North is all areas north of Amn split into two main territories, the Western Heartlands and the Savage Frontier.
The Sword Coast, and regional boundaries of its three city-states, is sometimes included in the territory of The North, or in the case of Baldur's Gate considered on the border of the Western Heartlands, but is also sometimes considered a separate territory along the coast of the Sea of Swords.