The Haltern Hills comprise the three ridges of Hohe Mark (146 m) , Borkenberge (133 m) and Haard (154 m) located respectively northwest, east and south of the German town of Haltern am See in Westphalia

Westphalia

Westphalia is a region in Germany, centred on the cities of Arnsberg, Bielefeld, Dortmund, Minden and Münster.Westphalia is roughly the region between the rivers Rhine and Weser, located north and south of the Ruhr River. No exact definition of borders can be given, because the name "Westphalia"...

. They are the only submontane subunit in the major natural region of Westmünsterland, and are found in the southeast of the region. Immediately to the east is the southwestern part of the Kernmünsterland

Kernmünsterland

The Kernmünsterland is a major landscape unit in western Germany. It covers an area of about 2700 km² and lies at the heart of the Westphalian Basin and the historic region of Münsterland in the north of Westphalia...

, also part of the Westphalian Lowland

Westphalian Lowland

The Westphalian Lowland, also known as the Westphalian Basin is a flat landscape that mainly lies within the German region of Westphalia, although small areas also fall within North Rhine and in Lower Saxony...

.

They are separated by the valleys of the rivers Lippe (northern boundary of the Haard with the other two ridges) and a line from the Halterner Mühlenbach via the Halterner Stausee and Stever

Stever

Stever is a river of North Rhine-Westphalia, Germany.-See also:*List of rivers of North Rhine-Westphalia...

 river to its confluence (eastern boundary of the Hoher Mark with the Borkenbergen).

The Haltern Hills, including the valleys that separate them, have an area of 283 km² in the southeast of the Hohe Mark Nature Park.