Ingram’s knock was the ninth highest ever for the county and the fifth longest recorded in terms of time, lasting three minutes short of 10 hours.
The veteran South African showed his lasting class with 28 fours and a six, looking completely at ease after dropped chances on 62 and 64.
He added 132 with Mason Crane, unluckily run out for a patient 49, while Fraser Sheat hit a quickfire 34 before the declaration finally came just before lunch.
Leicestershire saw off Glamorgan’s opening spells before Dan Douthwaite made things happen, starting with a no-ball and conceding two boundaries in his opening over then trapping Rishi Patel lbw for 23.
On a cool and breezy afternoon, on-loan rookie Ned Leonard nipped one back to clean up Foxes’ captain Lewis Hill in the next over, and Timm van der Gugten’s second spell saw Ian Holland lob to point after a battling 27.
The key partnership of Rahane (47 not out) and Handscomb (33 not out) should have been broken when Rahane, on 32, fired return catches to Crane off successive balls but the leg-spinner inexplicably put both down.
To add to his woes in the autumnal gloom, Crane then spilled a difficult chance offered by Handscomb off Leonard on 26, as Rahane curbed his attacking shots before rain followed by bad light cut the evening session to 45 minutes.
