The Gorges de l'Aude are accessed to the south of Quillan, itself south of Carcassonne (Languedoc-Roussillon region) of France. Quillan itself is a pleasant town, but with little in the way of great monuments. It is however well placed to explore both the Cathars castles to the east and the dramatic gorges to the south.
The road from Quillan to Axat passes through the deep gorge at Pierre-Lys, with cliffs either side of the road stretching to 700 metres in height. The road is in dreadful condition and requires strong nerves to negotiate it. Any barriers along the edge afford little more than token protection; large stretches should be taken at a snail's pace and a lookout kept for vehicles coming from the opposite direction!
Beyond Axat the route passes through the equally dramatic Gorges de Saint-Georges and Gorges de l'Aude. All three offer a very good opportunity to enjoy the landscape, either from the comfort of your car - it is said to be one of the most stunning drives in France - or as a starting point for walking and cycling in the region. Some vehicles drive very fast, and the main risk on this road is coming around a blind corner to discover a vehicle proceeding toward you at high speed. So, use caution and enjoy the magnificent scenery.
The narrowest and deepest stretch of the scenic Gorges de l'Aude is the eighteen or so kilometres between Axat and Usson. The road includes some steep sections, without market central lines, is very narrow, barely wide enough for 2 cars at the same time and it has not protections or guardrails. The surface of the road is asphalt. If you want to admire the scenery, don't drive: the road is much too dangerous to allow your eyes to wander.