Simon Kerrigan returned magnificent figures of seven for 63 as Northants, having started the final day on 123 for four, were bowled out for 241 with James Middlebrook top-scoring with 75 off 171 balls, giving Lancashire a target of 110.
The 2011 county champions then wrapped up the win thanks to Andrea Agathangelou's unbeaten 57 off 75 deliveries to move a point clear of their opponents with a game in hand.
Hampshire were also celebrating victory - only their second of the season in the Championship - after seeing off Glamorgan by 43 runs in a close-fought game in Cardiff.
James Tomlinson finished with figures of five for 44 while Danny Briggs took three for 33 as Glamorgan, having been set 221 to win, were bowled out for 177.
At Cheltenham, Alex Gidman's career-best 211 and Hamish Marshall's 106 guided Gloucestershire to an imposing 562 for five declared on the second day of their match with Kent.
But Gloucestershire's attack also found bowling on the placid College Ground pitch an equally arduous task as Kent reached 165 for two at stumps, thanks largely to an unbeaten 79 from Sam Northeast and 57 from Robert Key.
- Sports & Recreation
- James Middlebrook