Having lost 1-0 at home to Preston in the first leg on Thursday, Chesterfield fell to a 4-0 aggregate defeat overall at the hands of the Lilywhites after a 3-0 loss to Simon Grayson's men at Deepdale on Sunday.
The final three places in League 1 for the 2015/2016 campaign will be taken up by the losers of the other League 1 Play-Off Semi Final between Sheffield United and Swindon Town, the side defeated in the League 1 Play-Off Final and the winner of the League 2 Play-Off Final.
The full list of twenty teams confirmed in League 1 next season along with City looks like this:
Barnsley
Blackpool
Burton Albion
Bury
Chesterfield
Colchester United
Coventry City
Crewe Alexandra
Doncaster Rovers
Fleetwood Town
Gillingham
Millwall
Oldham Athletic
Peterborough United
Peterborough United
Port Vale
Rochdale
Scunthorpe United
Shrewsbury Town
Walsall
Wigan Athletic