The Yonne river flows through a valley which constitutes a true linear oasis, greener and much more inhabited than the surrounding plateaus. The most important towns in the department are in fact aligned along a North-West / South-East axis, which, over two-thirds of its length, is materialized by the Yonne valley. This axis corresponds to the historical route connecting the metropolises of Paris and Lyon via the Via Agrippa in the Gallo-Roman era then the royal road which became the RN6. This is where Joigny, crossed here by boaters on a river cruise, is located.