Gemeente Visit Geraardsbergen

Mark Valley

In the Mark Valley, you can enjoy the ‘Kluysbos’ with its beautiful spring flora and walk along old peat pits with hottonia palustris.

Description of the area

The Mark Valley is situated south of Geraardsbergen, straddling three provinces: East Flanders, Brabant and Hainaut. The Mark springs from Silly in Hainaut and discharges at Geraardsbergen into the Dender. Hydrographically, the valley forms part of the Dender basin. Despite the fact that the Mark has been straightened, which did mutilate the landscape to some extent, the drop in water level remained relatively limited. The valley retained its uniqueness to a large extent. In fact, since the dredging works stopped, the river has repaired some of the damage. Due to the alluvial deposits, the width is almost halved and the old meanders are recognizable again.

Apart from a few small pockets of ribbon development and a few scattered houses, this area is undeveloped. Hay fields cover a large area along the Mark. The small woods along the banks of the river Mark are mainly poplar plantations that have been planted during the last decades.

Hidden between the trees are old peat pits where peat was extracted as fuel in former times. These pits have since evolved into real gems with hottonia palustris and Lysimachia.

The ‘Kluysbos’ is located on the slope towards ‘Bosberg’. From the plateau, there are panoramic views over the Mark valley to the ‘Congoberg’ hills, the transmitter mast of St-Pieters-Leeuw and the tower blocks of Brussels. St Paul's Chapel is one of the oldest monuments of Galmaarden and is definitely worth a visit.

Animals and plants

Near the river, there are some old peat pits that, thanks to the intervention of local nature lovers, have been transformed into attractive ponds where the iris pseudacorus reigns supreme, although common skullcap, hottonia palustris and leman trisulca also thrive there.

The grey heron, which occupies a small colony in the wettest part of the wood, is easy to spot in the meadows. Anyone who wants to see the kingfisher breeding on the banks of the Mark must have a little bit more luck. The path along the Mark is the best place to spot this colourful bird.

The ‘Kluysbos’ is one of the region's most beautifully developed seepage woods. Especially in spring, you can enjoy the beauty of the flowers. Caltha, the great horsetail and carex pendula steal the show here. Higher on the slope, it is the primula elatior, the bluebells and ramsons that compete for the attention.


Freely accessible on the paths. Boots are recommended. Dogs must remain on the lead. The area is accessible via the red hiking path.

For more info and hiking maps, please click here.

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