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.

In many countries, kilometre zero or similar terms in other languages denote a particular location from which distances are traditionally measured and some use this as their official country location or coordinates for faster search at space satellites, this is also used for measuring distances between different countries around the world. Historically, they were markers where drivers could set their odometers to follow the directions in early roaming guide books.