Northwestern Europe, or Northwest Europe, is a loosely defined subregion of Europe, overlapping Northern and Western Europe. The term is used in geographic, history, and military contexts.
Geographically, Northwestern Europe is given by some sources as a region which includes Great Britain, Ireland, Belgium, the Netherlands, Luxembourg, Northern France, parts of Germany, Denmark, Norway, Sweden, and Iceland. In some works, Switzerland, Finland, and Austria are also included as part of Northwestern Europe.
Under the Interreg program, funded by the European Regional Development Fund, "North-West Europe" (NWE) is a region of European Territorial Cooperation that includes Belgium, Ireland, Luxembourg, Switzerland, the Netherlands and parts of France and Germany.
During the Reformation, some parts of Northwestern Europe converted to Protestantism, in a manner which differentiated the region from its Catholic neighbors elsewhere in Europe.
A definition of Northwestern Europe was used by some late 19th to mid 20th century anthropologists, eugenicists, and Nordicists, who used the term as a shorthand term for those regions of Europe in which members of the Nordic race were concentrated. For example, Arthur de Gobineau, the 19th-century aristocrat who published works on scientific racism, included parts of Northwestern Europe in what Leon Baradat described as his "Aryan heaven".
There is close genetic affinity among Northwest European populations, with some of these populations descending from related Corded Ware and Bell Beaker populations carrying large amounts of steppe ancestry. For example, the Beaker people of the lower Rhine overturned 90% of Great Britain's gene pools, replacing the Basque-like neolithic populations present prior.