These mountains, which are at the extreme southeast end of the East Hesse Highlands (Osthessisches Bergland), are partly a result of ancient volcanic activity.

In this gently rolling landscape numerous individual dome-shaped mountains rise on both sides of the border of Hesse and Thuringia and also, in some places, in Bavaria.

This river, which forms a wide and deep valley head flanked by the Dammersfeld ridge, flows to the southwest.

Numerous dome-shaped isolated mountains and hills rise above the valleys to 500–800 metres (1,640–2,625 ft), whose basalt covering is concentrated around the summit regions and does not blanket the entire landscape, as it does in the High Rhön.

This natural region runs northeast from the wide, pyramidal Pleß, 645.4 m (2,117 ft), far into the Bunter sandstone of the Stadlengsfeld Hills that descend to the River Werra.

In the west the Middle Felda Valley forms a natural boundary between Kaltensundheim in the south and below Dermbach in the north.

In the northeast of the region, the prominent kuppe of the Baier reaches a height of 713.9 m (2,342 ft), but its northernmost summit is the popular viewing mountain of Oechsen.

It reaches even greater elevations in the extreme southeast, where the Habelberg (718.5 m (2,357 ft)) west of Tann stands opposite to and north of the Auersberg.

This natural region is well known for the Hessian Skittles, a striking regular array of high, gently rounded, basalt cones up to 552.9 m (1,814 ft).

North and south of the skittles most of the kuppen in this natural region are also arranged in a row along the watershed between the Werra and the Fulda and between the Ulster and the Haune respectively.

The valleys of the Schmaler and Breiter Sinn running southwestwards, divide the natural region, which is clearly more heterogenous than the other ranges of the Kuppen Rhön, into three segments.

In the west, the rugged plateaux of dolerite and basalt transition into the Landrücken, whilst the northeast of the Kleiner Auersberg (c. 808 m (2,651 ft)) leads up to the Dammersfeld ridge.

Between the more rugged plateaux and ridges there are gently domed basalt intrusions that rise up, especially in the southeast, left of the Sinn near Bad Brückenau.

This term was coined by the Romans in Late Antiquity and described an ancient beech forest in the Rhön and the neighbouring low mountain ranges of the Spessart and Vogelsberg.

Due to the far reaching view from the Rhön mountains, they became sites for hilltop castles in the Middle Ages.

The higher beech woods are a habitat for rare, sometimes isolated, species of plant such as the Alpine blue-sow-thistle, giant bellflower and annual honesty.

Only small areas of the Rhön landscape are essentially open: the raised bogs (Hochmoore), the rock outcrops and the stone runs.

Growing amongst the rocks of the volcanic mountains are rare species such as Cheddar pink, sweet william catchfly, oblong woodsia and fir clubmoss.

Along the southern fringes of the Rhön, on the so-called slopes of steppe heathland (Steppenheidenhängen) grow warmth-loving plants such as white rock-rose, erect clematis and honewort.

Amongst the most valuable habitats in the Rhön are the mountain meadows and fields of mat grass (Nardetum strictae) on the higher slopes.

[6] Characteristic plants here include the monkshood, northern wolfsbane, common moonwort, martagon lily, greater butterfly orchid, perennial cornflower and wig knapweed.

There are also two species endemic to the Rhön: the rove beetle and a local snail, the Rhönquellschnecke (Bythinella compressa).

It is 137 km (85 mi) long and runs from Burgsinn in Main-Spessart district through Roßbach, Dreistelz, Würzburger Haus on the Farnsberg, Kissinger Hütte on the Feuerberg, Kreuzberg (monastery), Oberweißenbrunn, through the Red and Black Moors, over the Ellenbogen and the Emberg via Oberalba, past Baier to Stadtlengsfeld and on to its destination at Bad Salzungen on the Werra River.