Rotherham United spent most of the afternoon looking like they would stay in the second tier, but a late Cardiff equaliser saw the Millers slip into the bottom three.
In League Two, final-day wins for Cambridge United and Bolton Wanderers mean they are both celebrating promotions from the fourth tier.
League Two full-time headlines
Here's what today's results have done in the fourth tier:
Cambridge United and Bolton Wanderers have sealed automatic promotion.
Morecambe, Newport, Forest Green and Tranmere will contest the play-offs.
Cheltenham Town have wrapped up the League Two title
The play-off semi-final match-ups will see Morecambe face Tranmere and Newport take on Forest Green.
The first legs of those matches are on Thursday 20 May, with the returns on Sunday 23rd.
FULL-TIME
Oldham 0-3 Forest Green
A busy second half saw an Aaron Collins brace and Odin Bailey's goal give Forest Green a 3-0 away win to secure their play-off place.
FULL-TIME
Exeter 1-1 Barrow
Matt Jay's opener for the hosts was cancelled out by Tom Beadling's second-half equaliser for Barrow, meaning Exeter miss out on a play-off place.
Heartbreak for Matt Taylor's side.
Post update
Oldham 0-3 Forest Green
Seven minutes added on at Boundary Park.
FULL-TIME
Tranmere Rovers 0-0 Colchester United
Not a classic, but Tranmere have got the point they needed to book their play-off place.
FULL-TIME
Southend United 1-1 Newport County
Eventful game at Roots Hall that both sides could've won.
But the result means Newport have picked up the point they needed at the start of the afternoon to get themselves in the play-offs.
Cheltenham clinch League Two title
FT: Cheltenham 4-1 Harrogate
Already-promoted Cheltenham Town have wrapped up the title with victory over Harrogate.
It's a first-ever EFL championship for the Robins.
FULL-TIME
Morecambe 2-0 Bradford
Morecambe had a chance to win automatic promotion today, but the Shrimps will have to settle for a place in the play-offs after Cambridge and Bolton both win.
FULL-TIME
Crawley 1-4 Bolton
.Copyright: .
Bolton Wanderers clinch an immediate return to League One with a dominant win at 10-man Crawley.
It's back-to-back promotions for boss Ian Evatt, who led Barrow into the EFL last season.
HALF-TIME
Salford City 1-0 Leyton Orient
It's the interval at the Peninsular Stadium, but Salford City will soon know their fate with full-time whistles set to go elsewhere.
FULL-TIME
Cambridge 3-0 Grimsby
.Copyright: .
Cambridge United are back in the third tier after a 19-year absence.
Boss Mark Bonner seals promotion in his first full season as a manager.
GOAL: Crawley 1-4 Bolton
Davide Rodari (89 mins)
Ten-man Crawley pull a goal back late on through substitute Davide Rodari.
That's his first-ever goal in the EFL.
GOAL: Oldham 0-3 Forest Green
Aaron Collins (80 mins)
Aaron Collins runs from the half-way line, rounds Laurie Walker and slots it home into an empty net for his second of the afternoon.
GOAL: Salford City 1-0 Leyton Orient
Robbie Gotts (42 mins)
Salford City take the lead through a daisy-cutter from Robbie Gotts.
It doesn't look like it will make any difference to their slim play-off hopes with the scores elsewhere.
Post update
Exeter 1-1 Barrow
Unlucky for the hosts, as Ben Seymour runs to the byline and picks out Ryan Bowman in the box who should have done better, and he blasts the ball over from close range.
Exeter are throwing everything at this.
Post update
Southend United 1-1 Newport County
Josh Labadie has come off with what looked like a painful knee injury.
Matthew Dolan replaced him. Into the last five or so minutes.
One side bound for the National League, the other for the League Two play-offs.
Live Reporting
Rob Stevens, Adam Williams and Laura Savvas
All times stated are UK
Getty ImagesCopyright: Getty Images 
Getty ImagesCopyright: Getty Images - Cambridge United and Bolton Wanderers have sealed automatic promotion.
- Morecambe, Newport, Forest Green and Tranmere will contest the play-offs.
- Cheltenham Town have wrapped up the League Two title
.Copyright: . 
.Copyright: .
Latest PostTomorrow, we go again
#bbcefl
After some quite manic EFL games, it's time for us to say goodbye.
Thanks for joining us for the final day of the Championship and League Two campaigns.
Next up is the last round of League One fixtures tomorrow.
Do join us then, with three clubs battling it out for the final play-off spot.
Portsmouth are in the driving seat, but Oxford and Charlton could yet pip Pompey to sixth place.
Robins lift trophy
FT: Cheltenham 4-1 Harrogate
Cheltenham, meanwhile, have got their hands on the League Two title.
What a moment for Michael Duff's men - their first ever EFL silverware.
Bolton get the party started
FT: Crawley 1-4 Bolton
Bolton's players and staff have got their celebrations going at Crawley.
Wanderers will be back in League One next season after securing promotion at the first attempt.
Recap: Derby survive while U's and Bolton go up
If you are just checking in after an afternoon elsewhere, you have missed an action-packed day.
Derby County were the side who prevailed in the Championship relegation battle.
Wayne Rooney's Rams survived the drop thanks to a 3-3 draw against Sheffield Wednesday which consigned the Owls to League One.
Rotherham United spent most of the afternoon looking like they would stay in the second tier, but a late Cardiff equaliser saw the Millers slip into the bottom three.
In League Two, final-day wins for Cambridge United and Bolton Wanderers mean they are both celebrating promotions from the fourth tier.
League Two full-time headlines
Here's what today's results have done in the fourth tier:
The play-off semi-final match-ups will see Morecambe face Tranmere and Newport take on Forest Green.
The first legs of those matches are on Thursday 20 May, with the returns on Sunday 23rd.
FULL-TIME
Oldham 0-3 Forest Green
A busy second half saw an Aaron Collins brace and Odin Bailey's goal give Forest Green a 3-0 away win to secure their play-off place.
FULL-TIME
Exeter 1-1 Barrow
Matt Jay's opener for the hosts was cancelled out by Tom Beadling's second-half equaliser for Barrow, meaning Exeter miss out on a play-off place.
Heartbreak for Matt Taylor's side.
Post update
Oldham 0-3 Forest Green
Seven minutes added on at Boundary Park.
FULL-TIME
Tranmere Rovers 0-0 Colchester United
Not a classic, but Tranmere have got the point they needed to book their play-off place.
FULL-TIME
Southend United 1-1 Newport County
Eventful game at Roots Hall that both sides could've won.
But the result means Newport have picked up the point they needed at the start of the afternoon to get themselves in the play-offs.
Cheltenham clinch League Two title
FT: Cheltenham 4-1 Harrogate
Already-promoted Cheltenham Town have wrapped up the title with victory over Harrogate.
It's a first-ever EFL championship for the Robins.
FULL-TIME
Morecambe 2-0 Bradford
Morecambe had a chance to win automatic promotion today, but the Shrimps will have to settle for a place in the play-offs after Cambridge and Bolton both win.
FULL-TIME
Crawley 1-4 Bolton
Bolton Wanderers clinch an immediate return to League One with a dominant win at 10-man Crawley.
It's back-to-back promotions for boss Ian Evatt, who led Barrow into the EFL last season.
HALF-TIME
Salford City 1-0 Leyton Orient
It's the interval at the Peninsular Stadium, but Salford City will soon know their fate with full-time whistles set to go elsewhere.
FULL-TIME
Cambridge 3-0 Grimsby
Cambridge United are back in the third tier after a 19-year absence.
Boss Mark Bonner seals promotion in his first full season as a manager.
GOAL: Crawley 1-4 Bolton
Davide Rodari (89 mins)
Ten-man Crawley pull a goal back late on through substitute Davide Rodari.
That's his first-ever goal in the EFL.
GOAL: Oldham 0-3 Forest Green
Aaron Collins (80 mins)
Aaron Collins runs from the half-way line, rounds Laurie Walker and slots it home into an empty net for his second of the afternoon.
GOAL: Salford City 1-0 Leyton Orient
Robbie Gotts (42 mins)
Salford City take the lead through a daisy-cutter from Robbie Gotts.
It doesn't look like it will make any difference to their slim play-off hopes with the scores elsewhere.
Post update
Exeter 1-1 Barrow
Unlucky for the hosts, as Ben Seymour runs to the byline and picks out Ryan Bowman in the box who should have done better, and he blasts the ball over from close range.
Exeter are throwing everything at this.
Post update
Southend United 1-1 Newport County
Josh Labadie has come off with what looked like a painful knee injury.
Matthew Dolan replaced him. Into the last five or so minutes.
One side bound for the National League, the other for the League Two play-offs.