Thanksgiving Saturday at Gies Memorial Stadium
Saturday's game is on a rare date on the calendar for an IL home game. The Big Ten had almost always, with few exceptions here&there, wrapped up its regular season the week before Thanksgiving. When Nebraska was added as the 12th member in 2011 allowing the league to introduce the B1G title game, the league also normalized its schedule to match the rest of major CFB conferences and everyone had a game on Thanksgiving weekend ever since.
Below are the recent IL Thanksgiving Saturday home games, plus 2 earlier ones I found from the record book (not sure if this is a complete listing, I'm only going to go thru the record book once

). Listed is the result, records of the teams entering the game, and attendance numbers. Thanks to Jeff D'Alessio of the News-Gazette we have stadium attendance turnstile numbers for the most recent games as well.
These recent IL Thanksgiving Saturday home games have presented attendance challenges (both official & in stadium) because 1) Thanksgiving is a major holiday and a lot of people have left town combined with 2) the lack of excitement surrounding the program at that time for the regular season finale.
Saturday's game has a good chance of being the biggest IL Thanksgiving Saturday crowd ever (both official & stadium). Along with the largest growth in attendance in the nation from 2021-24, the biggest home opening crowd since 2009, 4-straight sellouts for the first time since 2008, great showings in IL's first time ever hosting a big pregame on-campus show, not a bad couple years for the fans. Go Illini
1962
W 7-6 (1-7 Illinois vs 5-3 Michigan State)
Official: 19,547
1990
W 28-23 (7-3 Illinois vs 2-8 Northwestern)
Official: 32,383
2013
L 34-37 (4-7 Illinois vs 4-7 Northwestern)
Official: 37,058
2017
L 7-42 (2-9 Illinois vs 8-3 Northwestern)
Official: 30,456
Stadium: 11,083
2019
L 10-29 (6-5 Illinois vs 2-9 Northwestern)
Official: 35,895
Stadium: 11,800
2021
W 47-14 (4-7 Illinois vs 3-8 Northwestern)
Official: 27,624
Stadium: 10,510
2023
L 43-45 (5-6 Illinois vs 6-5 Northwestern)
Official: 42,310
Stadium: 15,161
Link (fightingillini.com)
Link (N-G Jan 20, 2023)
Link (N-G Feb 23, 2024)