Derek McInnes' side hit the top spot on New Year's Day with a victory against St Johnstone, and an Adam Rooney double ensured they will stay there no matter what Celtic do on Monday against Kilmarnock.
The 26-year-old struck the opener after 36 minutes at Fir Park and he completed the win from the penalty spot after Stephen McManus had been sent off with two minutes to play.
Hamilton lifted themselves into third place thanks to Anthony Andreu's 12th goal of the season against 10-man St Johnstone.
The Frenchman fired past Alan Mannus 11 minutes before half-time to secure all three points for Alex Neil's side, and move them above Dundee United.
St Johnstone remain in sixth place, but they will be without James McFadden for their next match after the 31-year-old received a late red card for a second bookable offence.
Inverness Caledonian Thistle climbed to within a point of second-placed Celtic thanks to a 1-0 win over St Mirren, Billy Mckay grabbing the winner after 77 minutes.
Gary Mackay-Steven opened the scoring for Dundee United in their clash with Partick Thistle at the Firhill Stadium, but goals from Ryan Stevenson and Kris Doolan fired Thistle ahead at the break.
However, they were denied the win as Nafti Ciftci struck his ninth of the campaign with 17 minutes remaining to earn a point.
Meanwhile, United's city rivals Dundee were held to a 1-1 draw by Ross County courtesy of Craig Curran's 65th-minute strike, the visitors fighting back with 10-men after Terry Dunfield's early red card.
