Germania was the Roman name for roughly this geographical area. It includes most of today's Netherlands, Germany east of the Rhine and north of the Danube, southwestern Poland, most of the Czechia (all of Bohemia and most of Moravia), and a sliver of Austria. Things related to this province are Germanic; its people are Germanians (to distinguish them from today’s Germans).
North: North Sea, Eider River, Baltic Sea.
North of Eider River lies the Jutland Peninsula which is part of Incognita (Scandinavia).
East: Oder River and Morava River (which empties into the Danube).
To the east of the Oder River, Polonia; of the Morava, Dacia.
South: Danube River.
To the south: Noricum.
The Danube is the southern boundary of Germania because, north of it, Germanians were never part of the Roman empire; south of it, they were. Also, north of it Germanians went Protestant in the 1500s; south of it, they remained Catholic.
West: Rhine River.
To its west: Gaul.
All rights reserved. Fair use encouraged.