It comprised the region north of the Danube and Regensburg (Ratisbon), roughly covered by the modern Upper Palatinate stretching up to the river Main[1] and, especially after 1061, into the Egerland on the border with Bohemia.

The area east of Franconia proper up to the Bohemian Forest had been settled by Germanic Varisci and Armalausi tribes in ancient times; after the Migration Period, the forces of the proto-Merovingian king Chlodio (died c. 450) occupied the district.

[2] When King Charlemagne deposed Duke Tassilo III of Bavaria in 788, he entered the Nordgau and brought the Carolingian Empire into contact with Bohemia permanently.

[2] By an 806 deed issued at Thionville, Charlemagne separated out the Bavarian lands on the left bank of the Danube, including the ducal residences of Regensburg and Lauterhofen, called pagum, qui dicitur Northgowe.

There has been some confusion over whether or not the Nordgau was separated from Bavaria at this date or only as late as 976, when the East Franconian count Berthold of Schweinfurt, who had helped to suppress the rebellion of the Bavarian duke Henry the Wrangler against Emperor Otto II, was appointed margrave to administrate the region as a distinct march.