Classroom of the Elite season 4 appears to end around Year 2, Volume 2 , with episode 5 already reaching into the early part of that volume and later season coverage extending much further; one source even lists a Season 4 Episode 16 [END] entry, suggesting the season’s end point is near the later Year 2 material rather than the start of the arc.

What that means

  • If you want the anime-to-light-novel reading point , start from Year 2, Volume 2.
  • If you want the exact final chapter , available public results here do not give a reliable chapter number, so I can’t state one with confidence.

Best practical answer

The safest answer is: season 4 ends somewhere in the Year 2 early-volume material, around Volume 2, not a single clearly confirmed chapter.

TL;DR

Read from Year 2, Volume 2 onward to continue where season 4 leaves off.