Surprisingly little is known of the geographical history of Gaelic: where and when it was spoken in the past, and how and why the Gaelic-speaking area of Scotland – the Gaidhealtachd – has retreated and the language declined. A hundred years ago there were 250,000 Gaelic speakers. Now there are 80,000. This book answers four broad questions: What has been the geography of Gaelic in the past? How has that geography changed over time and space? What have been the patterns of language use within the Gaedhealtachd in the past? And what have been the processes of language change? Emphasis is upon the changing geography of the spoken language from 1698 to 1981: from the earliest date for which it is possible to document the expanse of the Gaelic language area to the most recent census to record the numbers speaking Gaelic.