Opener Paul Horton’s highest LV= County Championship score for 13 months helped to strengthen Lancashire’s hold over Roses rivals Yorkshire at Liverpool.
Horton’s second-day 93 off 199 balls - he shared a third-wicket stand of 81 with Mark Chilton - ensured the home side were eyeing their fourth win from five matches.
Chilton contributed a patient 77 off 174 balls, adding 90 with Steven Croft for the fourth wicket.
Yorkshire’s best spell of the day came just after tea when part-time Sheffield off-spinner Joe Root took two of three wickets to fall for the addition of four runs as the hosts slipped from 240 for three to 244 for six.
But, having been bowled out for 141 on the first day, the visitors were always playing catch-up.
Lancashire closed on 327 for eight from 113 overs. Luke Procter (23 not out) and James Anderson (four not out) will look to add to their lead of 186 today.
Horton, aged 28, was dropped on 73 by Rotherham wicketkeeper Simon Guy off Adil Rashid.