A stunning pass from man-of-the-match Michael Bridges put Lewis Neal through to give the Cumbrians the lead towards the end of the first half.
But just four minutes later the visitors were level when Luke Guttridge pounced to secure a draw that did little to help either side.
The Cumbrians started brightly without creating many chances although visiting keeper Chris Dunn constantly gave his defenders the jitters with a serious of flaps.
The game finally sparked into life on 26 minutes when Guttridge span debutant Ian Harte but the tricky midfielder could only watch on in frustration as his curling effort came back off the post.
But it was Carlisle that broke the deadlock thanks to a wonderful Bridges pass that dissected the Cobblers rearguard.
Neal was the man to take advantage as the ex-Preston winner calmly slotted his shot across Dunn for his second goal of the season.
Moments after that Carlisle's Cleveland Taylor fired over before top-scorer Danny Graham continued his miserable form when he failed to finish from three yards.
Northampton stormed back into contention when Liam Davis dropped a shoulder on the corner of the penalty area to outfox his marker and fire a vicious drive against the underside of the crossbar.
Seconds later the visitors were level when Davis' low shot was fumbled by keeper Ben Williams leaving Guttridge a simple finish as he fired into the roof of the net from ten yards.
The hosts should have had the chance to take the lead from the penalty spot in first-half stoppage time but, despite Giles Coke blocking Bridges' shot with both hands, referee Andy D'Urso waved away the furious appeals.
Another error in the second half from Dunn was cleared off the line by his own defender, Danny Jackman, as Carlisle pushed for a winner but it just wasn't to be for United as both sides failed to step away from the relegation zone.