As well as being a low mountain range, the Westerwald is also a natural region in the system of natural regional division of Germany. Within that it is a major unit group with the number "32". According to this system the major unit group of the Westerwald belongs to the basement plate (Grundgebirgsschollenland), which describes the type of mountain-building process by which it was formed. The major unit group extends across the states of Hesse, North Rhine-Westphalia and Rhineland-Palatinate. It is roughly bounded by the valleys of the Lahn (east and south), Rhine and Sieg (via Heller), whereby the hills immediately south of the Heller and Sieg are not considered to be part of it.
Natural region divisions Below the major unit group are the major units which, in turn, are divided into sub-units, part-units and base-units.Landschaften in Rheinland-Pfalz: WesterwaldMap and legend for the Westerwald in the Environmental Atlas of Hesse (Umweltatlas Hessen)Map service of the BfNMap service of Rhineland-Palatinate with maps of natural/landscape regions (→ Landschaftserleben → Landschaften in Rheinland-Pfalz)
320 - Gladenbach Uplands (780 km2) 320.0 Lahn-Dill Upland 320.00 Breidenbach Bottom 320.01 Bottenhorn Plateaux 320.02 Scheld Forest 320.03 Zollbuche 320.04 Hörre 320.05 Krofdorf-Königsberg Forest 320.1 Gladenbach Hills 320.10 Damshäuser Kuppen 320.11 Elnhausen-Michelbach Bowl 320.12 Salzböde Valley 320.13 Niederweidbach Basin 320.2 Upper Lahn Valley 321 - Dill Valley (174 km2) 321.0 Lower Dill Valley 321.1 Upper Dill Valley (with Dietzhölze valley) 321.2 Struth 322 - High Westerwald (346 km2) 322.0 Westerwald Basalt Plateaux 322.1 Neunkhausen-Weitefeld Plateau 323 - Upper Westerwald (669 km2) 323.0 Westerwald East Slope (Dill Westerwald) 323.1 Upper Westerwald Kuppenland 323.2 Dreifeld Weiherland 323.3 South Upper Westerwald Hills 323.30 Steinefrenzen Plateau 324 - Lower Westerwald (1316 km2) 324.0 Emsbach-Gelbach Heights 324.00 Horchheim Heights 324.01 Emsbach Valley 324.02 Plateaux of Welschneudorf 324.03 Gelbach valley 324.04 Eppenrode Plateau (Hochstein Ridge) 324.1 Montabaur Heights 324.2 Montabaur Basin 324.3 Kannenbäcker Plateaux 324.4 Rhein-Wied Ridge 324.5 Waldbreitbach Wied Valley 324.6 Sayn-Wied Plateaux 324.60 Isenburg Sayn Valley 324.7 Dierdorf Basin 324.8 Asbach-Altenkirchen Plateaux 324.80 Asbach Plateau 324.81 Altenkirchen Plateau 324.9 Rhine Westerwald Volcanic Ridge
The Westerwald in a narrower sense is generally considered to be the major unit groups 322 to 324.
References
External links BfN-Landschaftssteckbriefe: 320 Gladenbacher Bergland 320.0 Lahn-Dill-Bergland 320.1-2 Gladenbacher Hügelland und Oberes Lahntal 321 Dilltal 322 Hoher Westerwald 323 Oberwesterwald 323.0 Dillwesterwald 323.1-2 Oberwesterwälder Kuppenland und Dreifelder Weiherland 323.3 Südoberwesterwälder Hügelland (mit Gaudernbacher Platte) 324 Niederwesterwald 324.0-1, 324.3-6, 324.9: "Montabaurer Westerwald" 324.2, 324.7-8: "Niederwesterwald"
Literature Emil Meynen, J. Schmithüsen et al. (eds.): Handbuch der naturräumlichen Gliederung Deutschlands. Selbstverlag der Bundesanstalt für Landeskunde, Remagen, 1953–1962 (Part 1, contains issues 1–5), . Emil Meynen, J. Schmithüsen et al. (eds.): Handbuch der naturräumlichen Gliederung Deutschlands. Selbstverlag der Bundesanstalt für Landeskunde, Remagen, 1959–1962 (Part 2, contains issues 6–9), .