The Roman empire in the time of Hadrian (ruled 117-38 AD), showing, in central Gaul, the imperial province of Gallia Lugdunensis (north/central France). Note that the coast lines shown on the map are those of today, known to be different from those in Roman times in parts of Gallia Lugdunensis.
Gallia Lugdunensis (French: Gaule Lyonnaise) was a province of the Roman Empire in what is now the modern country of France, part of the Celtic territory of Gaul formerly known as Celtica. It is named after its capital Lugdunum (today's Lyon), possibly Roman Europe's major city west of Italy, and a major imperial mint. Outside Lugdunum was the Condate Altar, where representatives of the Three Gauls met to celebrate the cult of Rome and Augustus. Its original extent was from the rivers Seine and Marne in the north-east, which formed the boundary with Gallia Belgica, to the river Garonne in the south-west, which formed the border with Gallia Aquitania. Under Augustus, Gallia Lugdunensis was reduced in size. The portion between the river Loire and the Garonne was given to Gallia Aquitania, and central-eastern portions were given to the new province of Germania Superior. The map shows the extent after these reductions. It was an imperial province, deemed important enough to be governed by an imperial legate. Since Diocletian's Tetrarchy (296), it was the major province of a diocese confusingly called Galliae ('the Gaul provinces'), to which further only the Helvetic, Belgian (both also Celtic) and German provinces belonged; with the dioceses of Viennensis (the southern provinces of Gaul), Britanniae (also Celtic) and Hispaniae (the whole Celtiberian peninsula) this formed the praetorian prefecture also called Galliae, subordinate to the western emperor.