The ridge is a moraine, built during the Saalian glaciation when ice sheets reached this far south. Before they arrived, the Rhine and other rivers had laid down thick deposits of sand, gravel, and thinner clay layers across the region. The Saalian ice pushed those layers up into hills and gouged the valleys between them. The next glaciation, the Weichselian, never quite reached the Netherlands - the ice stalled in what is now the North Sea - but the cold permafrost at its edges shaped the landscape in another way. Wind-blown sand piled up against the frozen ground, and as the permafrost slowly thawed, it left behind the dry valleys that still seam the ridge today. By the time the Holocene warmed up 11,700 years ago, the bones of the Heuvelrug were already in place.

Forests covered the ridge for most of the Holocene. Then the medieval population grew, and people started using the landscape the way people did. Trees came down for lumber. Sheep and goats grazed the cleared ground. Farmers cut the top layer of sod and carried it to their fields as fertilizer. By the late Middle Ages, what had been deep forest was open heath with sand drifts blowing across it - so much so that by the late 1800s, foresters began replanting Scots pine, Douglas fir, and larch to hold the soil down. In the late twentieth century, the pendulum swung again. Conservation managers have cleared back stretches of forest to restore the heath, because the heath itself is now part of the cultural heritage - and because of one bird.

The black grouse - Lyrurus tetrix, Korhoen in Dutch - holds its courtship dance, called a lek, on open heath in the cold light of early morning. The males puff up their white tail coverts and make a sound somewhere between a coo and a bubbling rasp, and they have been doing it across northern Europe for as long as there has been northern Europe. They no longer do it anywhere else in the Netherlands. The Sallandse Heuvelrug holds the country's last breeding population, which is why the park's heath is managed so carefully - clipped, burned in patches, kept open against the slow advance of pine. The same heath supports the European nightjar, the European stonechat, and roughly eighty bird species that breed within the park. In the wetter hollows you can find common frogs, smooth and crested newts, and the slow worm in the dry uplands. Highland cattle and sheep do the trimming work the medieval farmers used to do.

Across 5,000 hectares - 2,700 of them inside the national park boundary south of the Nijverdal-Raalte road - the ridge is a small empire of footpaths and bike trails. The Dutch word for the experience is uitzicht, the view, and on the Heuvelrug the view is bigger than the elevation suggests. The horizon over central Overijssel curves gently rather than dropping behind a dike, and the air smells of resin and heather. Hikers and cyclists work the official routes between the visitor center on the N35 and outposts at Nijverdal, Holten, and Rijssen. Mountain bikers favor the sandier tracks. In winter the ridge does not become an alpine destination - the snow rarely lasts - but the trails take on a different quiet, and the pine canopy holds its color when the rest of the country has gone gray.

Two unexpected presences mark the modern park. One is the Canadian War Cemetery near Holten, where more than 1,300 Canadian soldiers killed in the final weeks of the Second World War lie under rows of white stones - a quiet field at the edge of the heath, oriented so the rising sun reaches each marker in turn. The other is the wolf. As wolves return to the Netherlands, sightings have been logged on the Sallandse Heuvelrug, though they do not yet hold territory here. The park's official advice is straightforward: keep your distance, and if a wolf approaches, scare it off. Dutch wolves are getting too comfortable around people, and on a small, densely settled ridge, that kind of comfort is what conservationists worry about most.