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This broad landscape includes four deep glacial valleys – Bonne, Béranger, Malsanne and Roizonne – that are cut into the western edges of the major crystalline massifs (Oisans and Écrins), along with sedimentary deposits that crop out only in the Malsanne Valley (Lias).

The first two valleys (Bonne and Béranger) are blind and abut against the ridges of the Écrins Massif. The two others (Malsanne and Roizonne) were sculpted by glacial transections during the Riss glaciation and open out onto the Romanche Valley (Col d'Ornon and La Morte).

The filled glacial basins of Valbonnais and Périer are perfectly flat and form small fertile agricultural enclaves that contrast with the surrounding mountains. The Valbonnais stands at the gateway to the Ecrins peaks, and contains the headquarters of the Parc national des Ecrins. Although it plays a substantial role in tourism, this has not had a major impact on roads and utilities.

In many ways, the lengthy Bonne Valley resembles the Vénéon Valley, so much so that one could speak of a twin valley. It is lengthy, enclosed and laid out in the same direction, and is occupied along similar gradients of density, from the populated bocage areas at the entryway and the broader western areas up to the woodlands and finally the exclusively mineral world of the high mountains at the foot of the legendary summits of Olan (3564m/11693ft) and Muzelle (3465m/1136ft).

After the two access points of Pont Haut and the Roizonne viaduct, the Bonne Valley first runs into the two small plains of Valbonnais and Entraigues. It has the same topography of a mountain bocage irrigated by canals as do the other flat-floored alluvial valleys, for example, the middle Romanche valley. But it stands out for the abundance of its fruit trees, in particular walnut trees, along with grain cropland and pastureland. Nevertheless, the horizons are marked by woodlands and the forest is closing in, in particular around Valbonnais, where it has begun to encroach into the village. A little further on, heading up the Malsanne, Le Périer has developed by taking advantage of another small plain.

The Valbonnais area is part of the Drac area and occupies a decisive role along the traditional itinerary between the east and the west of South Isère via D 526. It is, along with the Drac Valley road and the South Isère itinerary, the third most important itinerary in the area's road system. "This road forms part of the transversal territorial dynamics and ensures the connection between the Col de Menée and Valbonnais, and offers many vantage points over the landscape as one passes through distinct local areas that reflect the rich heritage of the entire region: the Vercors piedmonts, traditional Trièves], the Drac Valley, and the entrance into the Valbonnais on the edge of Matheysine and Beaumont" (Laverne).

It should be noted that developing this itinerary cannot be limited to the Valbonnais area but must also embrace the relationship of the Drac region with the Romanche Valley and the Bourg d'Oisans, via the Malsanne Valley, the Col d'Ornon (1367m/4485ft), and the Lignarre Valley, also on D 526. This is also the case for the Roizonne Valley and the rest of Alpe-du-Grand-Serre in the Taillefer massif, which are reached by D 114.