▁length ▁of ▁Brand ▁Highway ▁to ▁Ger ald ton , ▁and ▁then ▁along ▁North ▁West ▁Coast al ▁Highway ▁towards ▁Port ▁Hed land . ▁Highway ▁ 1 ▁enc oun ters ▁Great ▁Northern ▁Highway ▁again , ▁ ▁south - west ▁of ▁South ▁Hed land , ▁and ▁continues ▁north - east ▁along ▁that ▁highway . ▁From ▁this ▁point , ▁the ▁design ation ▁switch es ▁from ▁National ▁Route ▁ 1 ▁to ▁National ▁Highway ▁ 1 . ▁Highway ▁ 1 ▁follows ▁Great ▁Northern ▁Highway ▁north - east ▁to ▁Bro ome , ▁east ▁to ▁H alls ▁Creek , ▁and ▁then ▁north ▁to ▁Lake ▁Arg yle . ▁The ▁highway ▁then ▁turns ▁east ▁along ▁Victoria ▁Highway ▁to ▁Kun un ur ra ▁and ▁the ▁Northern ▁Territ ory ▁border . ▁ ▁History ▁Highway ▁ 1 ▁was ▁created ▁as ▁part ▁of ▁the ▁National ▁Route ▁Number ing ▁system , ▁adopted ▁in ▁ 1 9 5 5 . ▁The ▁route ▁was ▁compiled ▁from ▁an ▁existing ▁network ▁of ▁state ▁and ▁local ▁roads ▁and ▁tracks . ▁ ▁South ▁Australia ▁to ▁N ors eman ▁ ▁Due ▁to ▁the ▁on set ▁on ▁World ▁War ▁II , ▁supply ▁roads ▁leading ▁to ▁the ▁north ▁of ▁the ▁Australia ▁were ▁considered ▁vital . ▁Const ruction ▁on ▁the ▁E y re ▁Highway ▁first ▁started ▁in ▁July ▁ 1 9 4 1 ▁and ▁was ▁completed ▁six ▁months ▁later . ▁The ▁highway , ▁crossing ▁the ▁Null ar bor , ▁formed ▁just ▁by ▁grad ing ▁the ▁surface ▁material . ▁A ▁de cade ▁long ▁program ▁to ▁se al ▁the ▁highway ▁began ▁in ▁the ▁mid - 1 9 6 0 s