Portsmouth and Hartlepool joined Bury in being relegated to League Two next season despite neither side kicking a ball on Tuesday night.
Oldham's 1-0 win over Yeovil meants that neither Pools nor Pompey can catch the Latics.
Portsmouth's relegation is the culmination of a harrowing few seasons for the south coast club who were in the Premier League just three years ago and won the FA Cup in 2008.
That period has also seen the club go into administration twice but the Pompey Supporter's Trust were given the green light to take over the club last week and they will look to guide the club back from the fourth tier.
Hartlepool's fate was a far more straightforward affair with the appointment of John Hughes as manager in November unable to save them after a poor start to the season.
On the pitch on Tuesday evening, Matt Smith scored the only goal at Boundary Park as Oldham boss Lee Johnson secured bragging points over his father Gary in the Yeovil dugout.
The striker netted on the stroke of half-time to move the Latics five points clear of the drop zone with a game in hand over Colchester and Scunthorpe, who occupy 21st.
The Iron could be relegated at the weekend after losing 2-1 to Bury.
Karl Hawley gave the home side the lead but the relegated Shakers hit back with second-half goals from Jonson Clarke-Harris and Nick Ajose to leave Brian Laws' men on the brink.
Colchester are the side United will have to catch to avoid the drop and they were beaten 2-0 by MK Dons.
A goal in each half from Daniel Powell and Patrick Bamford left the Dons four points out the play-offs while Colchester have a five-point cushion over Scunthorpe.
At the other end of the table promotion-chasing Sheffield United and Brentford shared an eventful 2-2 draw at Bramall Lane.
Marcelo Trotta gave the visitors the lead from the penalty spot but the Blades were handed the chance to equalise as Tony Craig was sent off after conceding a spot kick when he brought down Dave Kitson.
Tony McMahon missed the penalty but Barry Robson was not so generous as he netted from the spot after Lee Hodson had handled in the area.
Dave Kitson then put United ahead but the home side went down to 10-men as Harry Maguire was dismissed for a second yellow card after conceding another penalty which was missed by Sam Saunders.
There was more drama to come as Clayton Donaldson was dismissed for a second booking before Bradley Wright-Phillips snatched a point for the Bees at the close.
In the night's other game a flying start from Swindon eased them to a 4-1 victory over Crewe.
Goals from Adam Rooney, Massimo Luongo and a second from Rooney had the Robins 3-0 up after 25 minutes before a Steve Davis penalty had Crewe back in contention.
But James Collins grabbed a fourth to for Swindon who remain in sixth.