Richard Cresswell's sixth-minute header put the Blades in front in an open first half that saw several chances go begging at either end of the field.
Paul McKenna drew Forest level after the break when his long-range effort proved too hot for United goalkeeper Steve Simonsen to handle and trickled over the goalline, but the hosts were unable to find a winner.
McKenna's strike stretched the Reds' unbeaten home league record to 24 matches, excluding their play-off semi-final defeat to Blackpool in May.
However, manager Billy Davies will surely be frustrated by yet another draw - his side's sixth from nine league matches this term.
Davies named the same starting XI that earned a 3-1 victory over Swansea at the weekend - the club's first home victory of the season.
Mark Yeates replaced the suspended Jamie Ward in United's line-up, while Daniel Bogdanovic and Ritchie De Laet came in for Ched Evans and Jean Calve.
Dexter Blackstock forced an early save from Simonsen at his near post. But it was the visitors who took the lead soon after as an unmarked Cresswell converted Stephen Jordan's inswinging free-kick from the right with a powerful header.
Blackstock headed against the crossbar for Forest two minutes later, but the flag had already gone up for offside.
The Blades then spurned a glorious opportunity to double their lead as Bogdanovic broke clear before firing directly at Lee Camp in the Forest goal.
Lewis McGugan was the next to threaten for the hosts, the in-form midfielder volleying narrowly wide following Blackstock's headed lay-off.
But United were quickly back on the attack themselves and Camp had to react well to keep out a sweetly-struck volley from Jordan which flew through a crowd of players.
Forest's Ryan Bertrand required treatment moments later after he was accidentally caught on the head by the studs of Cresswell as he made a challenge.
Fellow full-back Chris Gunter then beat Simonsen to a long ball forward, but the Wales international's cross was cleared to safety.
Camp pulled off a fine fingertip save to keep out a curling effort from Yeates as half-time approached, while the lively McGugan brought a more routine save from Simonsen.
There were fewer clear-cut chances after the interval as United became more content to defend their lead and look for opportunities on the counter-attack.
Dele Adebola was introduced in place of Guy Moussi just after the hour mark in a bid to bolster Forest's attacking threat.
And, after centre-half Wes Morgan had headed wide from a corner, the hosts did draw level as Simonsen failed in his attempts to tip McKenna's 25-yarder over the crossbar.
Simonsen almost handed Forest a second goal in the 79th minute when he dropped a cross at the feet of McGugan, but the midfielder's shot was blocked.
United then suffered an injury blow as Arsenal loanee Kyle Bartley was carried off following an aerial collision with Adebola.
Forest saw late appeals for a penalty waved away when Blackstock tumbled under a challenge from Johnny Ertl.
United held on thereafter in the face of mounting home pressure, despite the addition of six minutes of stoppage time following Bartley's injury.