Swindon were relegated from Sky Bet League One after a 2-1 home loss to Scunthorpe.
The Iron went 2-0 up through Murray Wallace's goal in the fifth minute and Sam Mantom's in the 71st, and despite Rohan Ince's long-range reply the 22nd-placed Robins were not able to save themselves.
To have a chance of surviving while losing, Swindon needed Bury to also be defeated, but the Shakers beat Northampton 3-0 at home with James Vaughan netting twice either side of a George Miller header.
While Scunthorpe, who are fourth, will definitely be in the play-offs, third-placed Fleetwood remain in the hunt for automatic promotion following their 3-2 come-from-behind victory at relegation-threatened Gillingham.
Kyle Dempsey struck the stoppage-time winner for the Cod Army after equalisers from Ashley Hunter and David Ball cancelled out Alex Cairns' own goal and Rory Donelly's effort.
Fleetwood's win meant second-placed Bolton, who are two points better off with each side having one game to go, were prevented from gaining promotion via their 2-0 victory at 10-man Port Vale.
David Wheater and Gary Madine got on the scoresheet after Rigino Cicilia was sent off in the 33rd minute.
Play was temporarily stopped temporarily in the second half after fans invaded the pitch following Wheater's goal.
Vale, in 21st place, are four points adrift of 20th-placed Gillingham and have two games left, while all the sides just above them have only one.
Bury are 19th and Shrewsbury 18th, five and six points clear of Vale respectively, after both recording wins on Saturday. Shrewsbury saw off Southend 1-0 at home courtesy of Junior Brown's second-half goal.
Oldham, who are 17th, guaranteed their safety with a 1-1 home draw against Rochdale. Peter Clarke levelled for the hosts after Callum Camps' opener.
Both seventh-placed Southend and eighth-placed Rochdale are still in with a chance of making the play-offs.
They are one and two points respectively behind sixth-placed Millwall, who lost 3-0 at home to Oxford. Conor McAleny notched an early brace that was subsequently added to by Joshua Ruffels.
Fifth-placed Bradford have a guaranteed play-off berth following their 3-0 home win over AFC Wimbledon, the goals coming via Tony McMahon's penalty, Mark Marshall's strike and another McMahon effort late on.
Elsewhere, champions Sheffield United won 3-0 at MK Dons, Leon Clarke's header followed by a Billy Sharp double.
Already-relegated Coventry beat Walsall 1-0 at home, with George Thomas striking the winner in the first half and Eoghan O'Connell being sent off for the visitors in the second.
The Sky Blues moved off the foot of the table, swapping places with Chesterfield, who are also already down. They lost 2-1 at home against Charlton as Jake Forster-Caskey and Ricky Holmes put the away side in charge before Reece Mitchell's late reply. Forster-Caskey subsequently had a penalty saved by Thorsten Stuckmann.
The day's other game was a 4-2 home triumph for Peterborough against Bristol Rovers.