Orient still moved to the top of the table after Dean Cox cancelled out Conor Coady's opener for the Blades with less than 10 minutes remaining.
The point was enough to see the O's go above Wolves on goal difference after they were beaten 1-0 at Peterborough.
Captain Michael Bostwick grabbed the Peterborough goal to end a run of five straight league defeats.
Elsewhere, Preston saw off struggling Bristol City 1-0 to stay third, easing past the side who sacked manager Sean O'Driscoll in midweek.
Jack King's first-half header claimed the points at Deepdale as both sides ended the game with 10 men after PNE midfielder Paul Gallagher and City defender Karleigh Osborne saw red in the 90th minute.
Bristol City stay 23rd however, with Notts County still bottom, after they lost 1-0 at home to Brentford.
Will Grigg's first goal since August sealed Brentford's victory.
Chuks Aneke's 80th-minute header gifted Crewe their first win in nine games as they overcame Crawley 1-0 despite being reduced to 10 men.
Crewe striker Vadaine Oliver was sent off in the 55th minute for his second bookable offence, but it was not enough to stop the home side from claiming victory.
Loan signing Chris Maguire scored two goals in the final four minutes to mark his Coventry debut by securing a 3-1 victory at MK Dons.
The striker's double sealed the deal after another new recruit, Barnsley loan arrival Chris Dagnall, opened the scoring.
Debutant James Tavernier claimed Rotherham's final goal in a 4-1 rout of Gillingham.
Noura Dicko, Kieran Agard, Ben Pringle and James Tavernier claimed the other goals for Steve Evans' men, with Cody McDonald registering for Gillingham.
Francois Zoko opened the scoring for Stevenage against Shrewsbury, but the home side slipped to a 3-1 defeat. Adam Reach, Tom Eaves and Joe Jacobson were on target for the visitors.
Swindon eased past Carlisle 3-1 at the Country Ground, with Massimo Luongo, Alex Pritchard and Dany N'Guessan in the goals.
Ryan Lowe's goal brace, including a score from the penalty spot, guided Tranmere Rovers to a 2-1 victory over Colchester as Clinton Morrison's 90th-minute score proved only to be scant consolation, while Port Vale won 2-0 at Walsall with goals from Tom Pope and Gavin Tomlin.