Sudetenland (Czech and Slovak: Sudety, Polish: Kraj Sudetów) is the German name used in English in the first half of the twentieth century for the northern, southwest and western regions of Czechoslovakia inhabited mostly by ethnic Germans, specifically the border areas of Bohemia, Moravia, and those parts of Silesia located within Czechoslovakia.
The name is derived from the Sudetes mountains, though the Sudetenland extended beyond these mountains which run along the border to Silesia and contemporary Poland. The German inhabitants were called Sudeten Germans (German: Sudetendeutsche, Czech: Sudetští Němci, Polish: Niemcy Sudeccy). The German minority in Slovakia, the Carpathian Germans, is not included in this ethnic category.
The areas later known as Sudetenland never formed a single historical region, which makes it difficult to distinguish the history of the Sudetenland apart from that of Bohemia, until the advent of and coining of the term nationalism in the nineteenth century.
In the Late Middle Ages the regions situated on the mountainous border of the Kingdom of Bohemia were since the Migration Period settled mainly by western Slavic Czechs. Along the Bohemian Forest in the west, the Czech lands bordered on the German stem duchies of Bavaria and Franconia; marches of the medieval German kingdom had also been established in the adjacent Austrian lands south of the Bohemian-Moravian Highlands and the northern Meissen region beyond the Ore Mountains. In the course of the Ostsiedlung, German settlers from the 13th century on also moved into the Upper Lusatia region and Duchy of Silesia north of the Sudetes mountain range.