The Blades sacked Nigel Clough nine days ago and are scheduled to announce his successor at joint-owner Kevin McCabe's London offices in Mayfair at 5pm.
Adkins, out of work for just under six months after being sacked by Reading in December 2014, will become the Blades' eighth manager since they were relegated from the top flight in 2007.
Bradford boss Phil Parkinson and out-going Brentford manager Mark Warburton had been among the candidates linked with the job
The Blades had an approach to talk with Parkinson turned down last week and it is understood the South Yorkshire club were not willing to trigger the get-out clause on the Bradford manager's contract, which has a year left to run.
Adkins began his professional career as club physio at Scunthorpe and was appointed manager following the departure of Brian Laws in November 2006.
He left Scunthorpe to succeed Alan Pardew as manager at Southampton in September 2010 but after two-and-a-half years in the role was replaced by Mauricio Pochettino.
Adkins was named Reading manager two months after being sacked by Southampton having led the Saints from League One to the Premier League in successive seasons, but was unable to prevent the Royals from being relegated from the top flight.
Source : PA
Source: PA