Lancashire secured LV= County Championship promotion after drawing their last home match of the season with Leicestershire at Emirates Old Trafford.
The Red Rose county claimed 11 points from the weather-affected fixture and with nearest rivals Essex being held to a draw by Kent at Canterbury, it meant the celebrations could start immediately.
Runaway leaders Lancashire will return to Division One with two matches remaining against Gloucestershire and Kent.
Winless Leicestershire battled hard on day four as they successfully avoided their eighth defeat of the season.
Resuming the final day on 60-3 in reply to Lancashire's first innings 453-7 declared, Ben Raine was instrumental in their close of play score of 329 all out with a career best 72 off 162 balls, including eight fours and a six.
The former Durham seamer has recently signed a one-year contract at Grace Road and the birthday boy, 22 today, beat his previous best score of 37 on debut for the Foxes last month.
Raine took advantage of good batting conditions, even hitting Andrea Agathangelou's off-spin for six over mid-wicket after tea.
He shared partnerships of 61 and 69 for the sixth and seventh wickets with captain Matt Boyce, who battled through an ankle injury to make 38, and Tom Wells. Raine hit his six after bringing up his 127-ball fifty, including seven fours.
Raine and Wells played aggressively during their 16.3 over alliance, which was brought to an end when the latter edged Kyle Hogg to second slip for 43 off 45 balls to leave the score at 253-7.
Wells, who also posted a career best, had hit England left-arm spinner Simon Kerrigan for six over long-on.
Earlier, Hogg struck the first blow of the day when he had Michael Thornely caught at slip as he gloved an attempted pull.
Kerrigan then had Niall O'Brien caught at leg slip for 63 before Boyce needlessly swept the left-armer to deep square-leg after lunch.
With Leicestershire in sight of avoiding the follow-on at 285-7, Raine's excellent innings was brought to an end when he attempted to pull Kerrigan but only top-edged to deep mid-wicket.
Tom Smith reduced the visitors to 304-9 when he trapped Ollie Freckingham lbw before James Sykes (34) was brilliantly caught by a diving Ashwell Prince after running back from the slip cordon following a top-edged at Smith.
The players shook hands immediately. Leicestershire take eight points into their last match of the season against Hampshire at Grace Road next week.