In the north, the valley of the Lahn (Giessen-Koblenzer Lahntal) with the Limburg Basin forms a very sharp scenic border to the northern Westerwald.

On the southern edge are the towns of Rüdesheim am Rhein, Wiesbaden, Hofheim am Taunus and Bad Homburg vor der Höhe at the junctions with the valleys of the Upper Rhine and Main; the towns of Bad Nauheim and Butzbach are on the eastern edge at the junction with the Wetterau; in the north on the Lahn the towns of Wetzlar, Weilburg, Bad Ems and Lahnstein border on the Hintertaunus; in the west in the Middle Rhine is, among other things, Lorch at the seam (each in an anti-clockwise direction).

The natural landscape is divided according to morphology, geological structure, climate and partly by the prevailing vegetation into sub-landscapes that are more uniform in themselves.

The Idstein depression widens towards the Lahn valley towards the Limburg Basin and is also known as the Goldener Grund in the northern area, probably because agriculture found more favorable conditions here.

[5] The oldest sedimentary rocks of the Taunus are the phyllites of Bierstadt from the Early Ordovician epoch, known only from a borehole in Wiesbaden, with an age of about 480 million years determined by the evidence of spores.

At the very southern edge and in a small deposit near Mühlbach in the east of the Vordertaunus unit, limestones are exposed that are attributed to the Middle Devonian.

The Lower Devonian sub-layer only appears in two small outcrops, metavolcanites of the type found in the Anterior Taunus rocks.

The clay slates of the Bunte Schiefer are greenish-grey or strikingly violet in color due to finely distributed hematite.

Agnaths (jawless fish) found in the Bunte Schist are from the Gedinne (Lochkovian); just like the formation of the rock, they show a deposit of the colorful slate in rivers or lakes.

The geology of the Hintertaunus is not as well known as that of the Vortaunus and Hochtaunus in the south or that of the Lahnmulde in the north due to the often monotonous sandy and slate rocks that form only a few continuous reference horizons and provide hardly any index fossils.

Transposed volcanic tuffes and ashes, the so-called porphyroides, are integrated into the Singhofen layers, they can be traced in some cases over several tens of kilometers.

[9] The Middle Devonian to Lower Carboniferous of the Usinger Mulde is only about 250 m thick and strongly tectonically disturbed, in the Lahnmulde and Dillmulde typical rocks of this time such as Schalstein, Massenkalk and deck diabase absent here.

[9] The strata of the Taunus were formed in the course of the Variscan orogeny foliated, scaled and in the southwest-northeast strike saddles and troughs folded.

Thus, at the fault zone of the Taunuskamm overthrust, the entire length of the southern Taunus nappe-like was thrust over rocks of the Younger Lower Devonian.

The overthrust of the Giessen Nappe, which lies flat today, on rocks from the Hintertaunus and the Lahn Mulde is of even greater extent.

The northwestern part of the Eastern Hintertaunus (Langhecker Lahntaunus), which leads to the Weilburger Lahntalgebiet, belongs geologically to the Lahnmulde and is rich in magmatism.

In the eastern Taunus between Idstein in the west and Usingen in the east, from the late Middle Ages to the early 20th century, there was a large number of pits in which there was mining of varying intensity on post-varistic, i.e. only after the varistic orogeny ore veins formed in the late Jurassic and early Cretaceous.

Exploration drilling carried out by the Hessian State Office for Soil Research in the 1980s no longer provided any indication of deposits worth building.

After the fall of the Limes (in 259/260 AD), the Alamanni settled in the range and for this reason there are some Alemannic cemeteries in the southern foothills of the Taunus (Eschborn).

The Latin “Taunus” comes from Tacitus, who wrote in his work Annales about a “castellum in monte tauno”, which probably referred to today’s Friedberg.