Late wickets from Ben Sanderson and Rob Keogh opened up a contest that’s anyone’s to win going into the final day at Wantage Road.
Bohannon shared a partnership of 117 with Steven Croft (47) to steer the Red Rose to 192 for five at stumps after losing both openers as they chased an awkward target of 278.
Earlier, Ryan Rickelton’s unbeaten 58 had guided Northamptonshire to 174 in their second innings, with Simon Kerrigan (43) helping him to add 95 for the eighth wicket despite Will Williams’ first five-wicket return in Championship cricket.
With drizzle and overcast conditions offering plenty of assistance for Lancashire’s bowlers both through the air and off the wicket, Tom Bailey (four for 65) got the fifth ball of the morning to nip back and dismiss Will Young lbw, while Luke Procter edged to first slip.
Emilio Gay weathered the storm, digging in to nudge Northamptonshire’s lead above 150, but his two-hour stay for 17 was ended by when he was adjudged lbw to Luke Wood.
Returning for a second spell before lunch, Bailey made deeper inroads as he found notable movement off the pitch to beat Lewis McManus’ defence before foxing a counter-attacking Tom Taylor with a slower ball.
Kerrigan played freely in his innings with Rickelton also regularly finding the boundary. While Rickelton pulled out the reverse sweep to combat Washington Sundar, Kerrigan fought a personal duel against Wood’s short-pitched bowling, taking a sharp blow on the hand but recovering to carve him over the slips for one of his six boundaries.
Kerrigan’s stay ended with a slice of luck for the visitors, Rob Jones fumbling the edge at slip but the ball ballooning up instead for Wells to grab.
Ben Sanderson and Jack White’s knocks were both brief, Rickelton left stranded as Northamptonshire finished with 174.
Sanderson struck in the third over of Lancashire’s chase when he found movement back to thump straight into Jennings’ front pad, Tom Taylor doing the same to beat the bat of Wells and trap him in front shortly after tea.
But Bohannon began to find his rhythm, chancing his arm against the spinners, and swept Rob Keogh for three boundaries in an over as Northamptonshire rotated the bowling without reward.
Sanderson kept Northamptonshire in contention by flattening the stumps of both Croft and Vilas late in the day and when nightwatchman Matt Parkinson also perished the contest swung again with a tantalising final day now in the offing.