Whoever prevails in Yorkshire will join either Dorking Wanderers or Ebbsfleet in moving into the fifth tier, those clubs meeting in the South final on the same day.
Match preview
Having finished more than 20 points behind second-placed Brackley Town during the regular campaign, the likes of York City and Boston United were clear underdogs when it came to securing promotion through the playoffs.
However, the two sides - who finished fifth and seventh respectively - have upset the established order, Brackley and third-placed AFC Fylde both being defeated in the semi-finals.
York's 1-0 success at the former was arguably more impressive, the Minstermen defying Brackley losing just five games and conceding 23 goals all season to prevail away from home thanks to Lenell John-Lewis's strike just before half time.
Nevertheless, on the same night, Boston rallied during the closing stages to defeat Fylde, a double from Danny Elliott sending the Pilgrims through to the final.
Elliott now has three goals to his name during the playoffs, the former Port Vale man also opening the scoring during the 2-1 win at Kidderminster Harriers in the previous round.
Although York had home advantage for their quarter-final tie with Chorley Town, John Askey's team had to dig in to prevail by a 2-1 scoreline.
York have now put together a seven-match unbeaten streak, their only defeat in 10 coming at Alfreton Town on April 18, while Boston are unbeaten in five outings, their solitary loss in nine games coming at home to Fylde on April 23.
Paul Cox's team put together a respectable away record during the regular campaign, collecting 28 points from 21 games and beating York in the corresponding fixture as recently as March 22.
Meanwhile, York accumulated 37 points from their 21 home fixtures, the most recent of six defeats coming in that game almost two months ago.
York City National League North form:
Boston United National League North form:
Team News
Having picked up an injury during the Brackley game, John-Lewis is expected to miss out for York.
Kurt Willoughby looks most likely to deputise in attack, but Askey has suggested that he will consider changing formation.
Remy Longdon and Josh King are both pushing to come back into contention after injury.
Cox made only one substitution during the semi-final, introducing Jake Wright for Ntumba Massanka just before the hour mark.
If a change is made to the Boston XI, that is likely to be the only alteration, Wright having earned the penalty for his side's match-clinching goal.
York City possible starting lineup:
Jameson; Dyson, Kouogun, Sanders, Barrow, Wright, Hancox, McLaughlin, Kouhyar, Willoughby, Donaldson
Boston United possible starting lineup:
Dewhurst; Seriki, Shiels, Garner, Ferguson; Byrne, Abbott, Green, Dimaio; Massanka, Elliott
We say: York City 2-1 Boston United
Boston have relished their tag of underdogs in the previous two ties, and it is something which York will no doubt be wary about heading into this fixture. Nevertheless, we cannot ignore that York are on the longer unbeaten streak, leading us to predict a narrow win for the home side, potentially after extra time.