The hiring was first reported by Fox Sports and ESPN, with both outlets saying final details were still being worked out Tuesday night. The Raiders had no immediate comment on the reports.
New general manager Reggie McKenzie decided on his new coach exactly two weeks after he was hired. He immediately fired Hue Jackson, who went 8-8 in his only season as coach, and began the search.
With McKenzie having spent almost two decades with the Packers, his former colleagues in Green Bay were originally considered to be the favorites. But instead he went with the 39-year-old Allen, coming off his first season in the NFL as a coordinator. Allen had his second interview with McKenzie on Tuesday at the Senior Bowl in Mobile, Ala.
After Madden retired, Davis exclusively hired offensive coaches: Tom Flores, Mike Shanahan, Art Shell, Mike White, Joe Bugel, Jon Gruden, Bill Callahan, Norv Turner, Shell again, Lane Kiffin, Tom Cable and Jackson. Allen will be Oakland's seventh coach since the 2003 season in his first head coaching job at any level. The Raiders have not had a winning record or made the playoffs since Callahan took them to the Super Bowl following the 2002 season.
There have been plenty of changes for the Raiders since Davis died Oct. 8. His son, Mark, took over the team and hired McKenzie after the season to take over many of the on-field and personnel decisions that Al Davis had made during his nearly half-century with the organization. Davis also was heavily involved in the defensive schemes with some people referring to him as the de facto "defensive coordinator."
In his first season as coordinator in Denver, Allen helped the Broncos improve from allowing a league-worst 29.4 points and 390.8 yards per game to ranking 20th in yards (357.8) and 24th in points (24.4) this season on the way to an AFC West title.
The Broncos increased their sack total from 23 to 41 and were tied for the sixth-most blitzes on pass plays in the league this season, according to STATS LLC.
Allen had served as New Orleans' secondary coach the previous five seasons and had also coached for Atlanta. He runs a 4-3 defense, which the Raiders have used the past seven seasons.
The Raiders, however, struggled mightily on defense this past season despite giving big contracts in the offseason to Richard Seymour, Kamerion Wimbley and Stanford Routt. Oakland had franchise worsts in touchdown passes allowed (31), yards per carry (5.1), yards passing (4,262) and total yards (6,201), while giving up the third-most points (433) in team history.
Oakland joined this year's Tampa Bay team as two of the four teams to allow at least 30 TD passes and 5.0 yards per carry in a season, a distinction achieved previously by only the 1950 Baltimore Colts and 1952 Dallas Texans. The Raiders also became the sixth team since the 1970 merger to allow at least 2,000 yards rushing and 4,000 yards passing in a season.