Gérac Circus, Natural rock cirque and hiking trail in Ustou, France

The Cirque de Gérac is a natural rock bowl in the Pyrenees near Ustou, France, forming both a geological landmark and a hiking trail through steep mountain terrain. The route crosses rocky passages, alpine meadows, and small streams, and passes by the Étang d'Aubé, a glacial lake, before reaching the Pic Séron at about 8,160 ft (2,489 m).

The landscape around Cirque de Gérac was shaped over thousands of years by glaciers and water erosion, which carved out the rock walls, hollows, and bowl shape visible today. The Couserans region it belongs to has a long history of seasonal herding, with farmers moving livestock to high pastures each summer for centuries.

The name "Gérac" comes from an old local mountain dialect and reflects the long pastoral tradition of the area, where sheep farming has shaped the land for generations. Today, hikers often walk past free-roaming herds and may even encounter shepherds watching over their animals on the slopes.

The trail starts from a parking area already at elevation above Ustou, which cuts down the initial climbing effort somewhat. Some sections involve chains and ropes on steep rock, so sturdy footwear and enough water are essential, and the descent requires careful footing on loose gravel.

From the top of Pic Séron, on a clear day you can spot the summits of Pique d'Estats and Montcalm, two of the tallest peaks on the French side of the Pyrenees. Just below, the Étang d'Aubé shifts between deep green and turquoise depending on the light, making it one of the more eye-catching mountain lakes in the area.