The Route nationale 20 (N20) is a trunk road (nationale) between Paris and the frontier with Spain heading south through the heart of France and passing through the Cathedral City of Orléans and Toulouse. The road forks at Col de Puymorens with one branch being the Route nationale 22 which leads to Andorra. In winter, avalanches sometimes close the road.

A route nationale, or simply nationale, is a class of trunk road in France. They are important roads of national significance which cross broad portions of the French territory, in contrast to departmental or communal roads which serve more limited local areas.