Stadium: Proact Stadium
Nickname: The Spireites
Position: Sixth in League One
Manager: Dean Saunders was handed a two-year contract as Chesterfield's new manager on 13th May 2015 following Paul Cook's departure for Portsmouth.
Cook left the Spireites for Pompey after guiding them to the League One Play-Offs, where they were beaten 4-0 on aggregate by eventual Play-Off Final winners Preston.
Former Liverpool and Welsh international striker Saunders has previously managed Wrexham, Doncaster and Wolves.
He finished the 2014/15 season in interim charge of Crawley having stepped in last December after John Gregory underwent major open heart surgery, but was unable to prevent them from being relegated to League Two on the final day of the season despite Saunders winning eight of his 24 League games in charge.
Crawley's relegation means Saunders has now taken a team down in three of the last four seasons after being in charge when Doncaster were relegated from the Championship in 2012 and being unable to save Wolves from the same fate the following year.
Key Player: Attacking midfielder/right-back Tendayi Darikwa was one of the first names on the Chesterfield teamsheet last season - in fact he was on each and every of the 56 teamsheets as he became the Spireites' first ever-present outfield player in a season since Tom Curtis in 1995-96.
Born in Nottingham, Darikwa came through the ranks at Chesterfield and made his debut as a sub against Burton in the FA Cup in November 2010, making his League debut at Notts County soon after.
The 23-year-old was a marauding midfielder in his early days, but manager Cook saw his potential as an attacking right-back, and switched him to that position with great success.
Tendayi's consistent performances during the course of last season saw the club's fans vote him their Player of the Year.
Top scorer: James O'Shea (9 goals)
Head-to-head: The Spireites and Lions have met on 35 previous occasions and Millwall hold a narrow advantage with 15 wins to Chesterfield's 13 in all competitions. The remaining seven matches have finished all square.
Home advantage definitely seems to play a part when these two teams meet with 11 of Chesterfield's 13 victories against Millwall coming on their own turf, compared to 10 from 14 for The Lions.
Whether there is a shift in home comfort now that The Spireites have moved from Saltergate to their new Proact Stadium remains to be seen. Time will tell!
Last time we met: You have to go back to Saturday 10th February 2007 to find the last meeting between these two teams - and it took a rare goal from sub Paul Hubertz to grab the clincher in a 2-1 home win.
Darren Byfield had fired The Lions into a 10th-minute lead only for visiting striker Paul Hall to level things up 13 minutes after the break.
The game looked to be heading to a draw when up popped Hubertz, a 72nd-minute replacement for Neil Harris to snatch victory with five minutes remaining. It was sweet revenge for The Lions, who had been on the end of a 5-1 drubbing at Saltergate earlier that season.
Millwall: Pidgeley, Senda, Phillips, Craig, Robinson, Elliott, Brighton, Brammer, Harris (Hubertz, 72mins), Byfield (Morris, 89mins), Williams (Hackett, 72mins). Subs not used: Day, Fuseini.
Scorers: Byfield (10mins), Hubertz (85mins)
Chesterfield: Jordan, Picken, Critchell (Davies, 66mins), Grimaldi, Hazell, Allott, Niven, Holmes, Shaw (Allison, 85mins), Ward, Larkin (Hall, 46mins). Subs not used: Roche, Downes.
Scorer: Hall (58mins)