United will take on Swindon Town in League One next season.
It comes following the Robins' 4-0 defeat to Preston North End in the play-off final on Sunday night.Congratulations to Simon Grayson's Lilywhites, who saw former Iron striker Jermaine Beckford strike a hat-trick to help secure the win at Wembley.
They will be plying their trade in the Championship next season.