Corry Evans helps Rovers return to the Championship
Northern Ireland midfielder Corry Evans will be back in the Championship next season after Blackburn clinched promotion with a dramatic 1-0 victory at Doncaster.
With Shrewsbury coming from behind to beat Peterborough, it looked like Rovers would have to wait to secure a top-two spot in Sky Bet League One.
But Charlie Mulgrew finally rewarded the Lancashire side for all their second-half pressure when he headed home with 10 minutes remaining at the Keepmoat Stadium.
Adam Armstrong had earlier hit the woodwork for the visitors, who will join leaders Wigan in the second tier next season.
Third-placed Shrewsbury had threatened to keep up the pressure on Blackburn despite falling behind to a 14th-minute strike from Peterborough's Gwion Edwards at New Meadow.
Omar Beckles equalised just before the hour and Stefan Payne put them on course for victory 17 minutes from time. Lenell John-Lewis added a third in injury time but the Shrews will have to settle for a place in the play-offs.
Nottingham Forest left Barnsley fighting for Championship survival as Aitor Karanka's side cruised to a comfortable 3-0 success at the City Ground.
Lee Tomlin scored a spectacular goal of his own, before setting up another for Ben Brereton, and sub Apostolos Vellios netted a late third, as Karanka dealt a severe blow to his old friend, Tykes boss Jose Morais.
Cardiff's automatic promotion hopes were dented as Derby revived their play-off hopes with a 3-1 win at Pride Park.
The visitors looked comfortable after Callum Paterson gave them a half-time lead but defensive errors allowed Cameron Jerome to score twice either side of a Matej Vydra strike as Derby ended a run of three defeats to move back into the Sky Bet Championship top six.