The Col de Peyresourde sits at 1,569 metres on the border between the Hautes-Pyrénées and the Haute-Garonne, and it is one of those passes that you cross without much ceremony but remember for the road. The D618 goes up from the Louron valley on one side and drops to Bagnères-de-Luchon on the other, and in between it is a ribbon of well-surfaced bends through grassy slopes, with wide views toward the high Pyrenean peaks. It is not a hard climb, but the setting is fine, and there is a modest ski station, Peyragudes, near the summit.
The south side, toward Luchon, is the more interesting. The road descends in a series of fast, open curves, passing through the village of Garin and following the green valley down toward the spa town. The surface is generally good and the gradient moderate, making it an enjoyable descent when the traffic is light. In summer, you will often share the road with cyclists, who know the pass well from the Tour de France, and with caravans, so patience is useful. Cattle graze the high pastures and may stray onto the road, particularly near the top.
Weather rules the mountain. Fog can drift in without warning, wind blows across the open crest, and temperatures at the top can be a good deal cooler than in the valleys. In winter the pass is open more often than some of its neighbours, but snow and ice are possible, so check before you set off. Late spring and early autumn offer the best combination of clear air and quiet roads. In the evening, the light on the peaks to the south is warm, and the temperature drops quickly.
The Pyrenees here are a rich area for wildlife and traditional pastoralism. Pastures at the top are grazed by cows and sheep in summer, in a system of transhumance that goes back centuries, and griffon vultures soar on the thermals above the slopes. Look for marmots near the rocks.
Services are limited at the pass itself, though a small café and a ski-station building can be open in season. For fuel, the nearest sure source is Bagnères-de-Luchon, about ten kilometres down the south side, or Arreau on the north. Vielha, across the border in the Spanish Val d'Aran, is the nearest larger town, but the border is a longer ride, so plan your fill-up on this side.