The Iron age ain't really my bag but I believe that a number of shrines/altars dedicated to Brigantia have been found around the north of England.
Elgee discusses the possible meaning of Brigante as a hill dweller or highlander.
There were other Brigantes in Europe
Ptolemy records the Brixante and the city of Briantium just north of the modern cities of Grisons.
Strabo placed his Brigantii on the shore of Lake Constance. Ptolemy also put a group of Brigantes in south east Ireland, close to the River Barrow (Fluvius Bergus).