A vidde is an open, treeless mountain plateau - the broad, gently rolling upland country that, more than the dramatic vertical fjords, defines what most of inland Norway actually looks like above the treeline. The plural is vidder. The largest in the country, and the largest in northern Europe, is the Hardangervidda, an 8,000-square-kilometer plateau between Bergen and Oslo that supports the country's largest wild reindeer herd.
The geography is distinctive and unlike anything in continental Europe. A vidde sits at 1,000 to 1,400 meters altitude, has minimal tree cover (cold and exposed conditions limit vegetation to dwarf birch, lichen, mosses and short grasses), and runs for tens of kilometers in any direction. The horizons are long, the weather changes quickly and visibly, and the sense of scale is closer to what travelers normally associate with the Hebrides or with high Patagonian country than with continental European mountains.
Walking on a vidde is a different experience from walking in the fjord-edge mountains. Gradients are gentle. Distances are long. There is little protection from weather; serious storms can develop quickly and visibility can collapse to a few meters. The classic Hardangervidda crossing - a four-to-six day east-west traverse from Halne to Kinsarvik - is one of the routes where we usually recommend a local guide rather than going independently, particularly for travelers without serious mountain experience. The Norwegian Mountain Code applies in full.
Three vidder are particularly worth knowing about. Hardangervidda is the largest and the home of the wild reindeer. Hallingskarvet is a single long ridge anchoring the eastern Hallingdal valley, with two DNT cabins and one of the country's most consistent landscapes for sustained high-altitude walking. Finnmarksvidda, in the far north, is the broader open country of the Sami reindeer-herding tradition. Each rewards a slow, respectful trip rather than a fast one.