In the final Party Vote for Whangārei Labour got 20,942 votes compared to National's 11,602.
In the Northland electorate Prime got 17,066 votes, compared to King's 16,903, for a 163 vote majority. But given the closeness of the margin, King has said he will go for a recount.
In the party vote in Northland Labour got 19,997 votes compared to National's 12,496.
The result is an historic shock - this is first time Labour has held both seats at the same time - it had only held Whangārei once - from 1972-1975, and last held Northland in 1938.
It's also the first time ever that Labour won the party votes in both electorates.
Prime was ecstatic in the minutes after hearing the news she had taken the electorate - the first time Labour has done so since 1938.
"I was shaking when I found out," said Prime.
"I can't believe it. It is a dream come true."
Prime was well aware of the 82-year gap since Labour had won an earlier iteration of the electorate. The seat of Bay of Islands was won by teacher and trade unionist Charles Boswell for a single, extended, war-time term.
"I am humbled so many people voted for me," said Prime.
"I had always tried to be the best voice and representative for Northland in Parliament whether I'm a list or electorate MP.
"I knew when I put my hand up in 2014 it was going to be one hell of a battle in such a safe blue seat. It's been a roller coaster ride with so many twists and turns. I will continue to do the best I can for Northland."
If the final result for Northland is maintained after a recount it will see King leave Parliament after one term.
However, if Henderson is confirmed as Whangārei MP Reti wills till be in Parliament as he is highly placed on the National Party list.
Reti has yet to make a decision on whether to seek a recount.