The Cobblers created the better chances throughout the game but had to wait until midway through the second half to make the breakthrough.
Akinfenwa, who earlier headed against a post, nodded home Ben Tozer's cross after 69 minutes for his 15th goal of the season.
Clive Platt tested Dean Lyness with an early header and Jake Robinson flashed a shot across the face of goal.
The influential Chris Hackett went close with a curling effort, Akinfenwa twice headed wide and Ben Harding's close-range effort was blocked before Luke Gutteridge saw an acrobatic volley flash wide.
It was not until early in the second half that Burton produced their first effort on goal when Lee Bell fired over.
Jacques Maghoma should have done better following a promising move but Northampton still looked the more likely to score and Harding had another effort blocked.
The breakthrough finally came when Tozer's cross found Akinfenwa who headed over the stranded Lyness.
Maghoma was denied a quick equaliser when his shot was deflected over and Damien McCrory was denied by Lee Nicholls as Albion finally showed some urgency in the final third, but it came too late for them to get anything out of the game.
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