The 24 teams that will take part in Sky Bet League One in the 2023/24 season were confirmed at the end of May.
Here, dcfc.co.uk will take a look at each one in focus ahead of the new campaign getting underway at the start of August.
First up, a familiar foe from last year in Barnsley.
Fact File
Established: 1887
Nickname: The Tykes
Home: Oakwell Stadium (23,287 capacity)
Manager: Michael Duff
2022/23 finish: 4th (Sky Bet League One)
Club History
Founded in 1887, Barnsley's club colours were initially blue before they changed to what we know them as now - red and white - in 1904.
Twice they have managed to reach the Final of the FA Cup, both times whilst they were playing their football in the second tier. A 1-0 loss to Newcastle United in 1910 was then bettered in 1912 and they got their hands on the historic trophy following a 1-0 victory over West Bromwich Albion.
They secured Premier League football in 1997/98 but were relegated after just one season in England's top tier.
In more recent years they got their hands on the silverware that is the Football League Trophy - an entertaining 3-2 victory over Oxford United at Wembley Stadium seeing them earn the honours in 2016.
Despite now being in the third tier, Barnsley have spent more seasons and played more games at the second level of English football than any other team.
Played For Both
Sam Winnall
Striker Sam Winnall turned out for both the Reds and the Rams in recent years, although his stint in Derbyshire was only on loan.
His period at Oakwell between 2014-2017 was arguably the most successful in his career and he scored an impressive 48 in 115 for the Tykes.
In 2017 he made the move to Sheffield Wednesday and that same year he made a season-long loan switch to the Rams.
He scored six in 18 for Derby in the 2017/18 season before suffering an ACL knee injury in early 2018 which ruled him out for the rest of the campaign.
Jason Shackell
Central defender Jason Shackell had a brief spell at Barnsley, but was still able to make an impression in that time, as well as two stints with Derby.
Shackell captained the Tykes in 2010/11 and his impressive performances saw him earn a move to Pride Park after just one season.
Like in Yorkshire, he was an ever-present for the Rams and again spent just one season at the club, appearing 49 times, before earning a move to Burnley in the summer of 2012.
He returned to Derby in 2015 and went on to make a further 62 appearances to take his total for the club up to 111 before departing on a free transfer in the summer of 2018.
Conor Hourihane
There is, of course, a member of the current Rams squad that used to line up for Barnsley too in Conor Hourihane.
After bursting onto the scene at Plymouth Argyle, Hourihane made the move to Yorkshire with the Tykes in the summer of 2014.
After impressing during his first season, the midfielder was then made club captain in December 2015.
He had much success with Barnsley and in 2016 was a key part of the squad that lifted the Football League Trophy before then returning to Wembley a few months later as the team won promotion to the Championship via the play-offs.
2022/23 Season
Last season was a case of so very nearly for the Tykes.
After totalling up an impressive 86 points and a fourth-place finish in the regular campaign, Michael Duff’s side were able to book a place at Wembley Stadium in the League One Play-Off Final following a 2-1 aggregate victory over Bolton Wanderers in the Play-Off Semi-Finals.
The Play-Off Final against Yorkshire rivals Sheffield Wednesday went the distance and despite having a man disadvantage for the entire second-half, the Tykes forced extra-time.
It looked destined for penalties until Josh Windass headed in for Wednesday with three seconds remaining to ensure it was the Owls heading back to the second tier with a 1-0 win - and Barnsley who would once again face the Rams in Sky Bet League One.
Record Against The Rams
The Rams and the Tykes were able to take three points each off each other last year in League One after an early season 2-1 victory for Derby at Pride Park Stadium, with a Conor McCarthy own goal and a Nathaniel Mendez-Laing strike proving vital, was avenged by Barnsley who landed a 4-1 win at Oakwell. David McGoldrick was on the mark for Derby on an afternoon to forget in South Yorkshire.
The two did however meet three times in 2022/23 with the Rams securing an impressive 3-0 victory in Emirates FA Cup Third Round action.
Historically it is Derby that have got the better of the two landing 37 victories to Barnsley’s 23 whilst on 17 occasions the spoils were shared.
Barnsley were Derby's first-ever competitive opponents at Pride Park Stadium in August 1997, after the initial first game against Wimbledon was abandoned due to a power failure, with Stefano Eranio scoring from the penalty spot in a 1-0 win in the Premiership.
The first meeting between the two sides dates way back to 1897 when the Rams thumped their Yorkshire opponents 8-1 in the FA Cup.