The Scottish Highlands, known locally simply as the Highlands (Scottish Gaelic: A' Ghàidhealtachd, "the place of the Gaels"; Scots: the Hielands) are a historic region of Scotland. The region became culturally distinguishable from the Lowlands from the later Middle Ages into the modern period, when Lowland Scots replaced Scottish Gaelic throughout most of the Lowlands. The term is also used for the area north and west of the Highland Boundary Fault, although the exact boundaries are not clearly defined, particularly to the east. The Great Glen divides the Grampian Mountains to the southeast from the Northwest Highlands.