Three entities known (or partly known) as Westphalia, shown on the modern state borders of Germany:
Green: Kingdom of Westphalia (1807-1813), borders as of 1811
Red: Province of Westphalia (1815-1946)
Dark grey: North Rhine-Westphalia (since 1946)

Westphalia (German: Westfalen) is a region in Germany. The cities of Arnsberg, Bielefeld, Bochum, Detmold, Dortmund, Gelsenkirchen, Hagen, Minden and Münster are in its centre. In 1946, the state of North Rhine-Westphalia was created, which includes part of the historical region.