Well, it's a bit tricky to pinpoint exactly where the anime ended in the manga. It depends on various factors like story arcs and pacing. But generally, you can find out by comparing key events and plot developments.
The ending of One Punch Man manga is quite unexpected. Saitama faces a powerful final enemy but resolves the situation with his trademark one-punch style, while also bringing some closure to character arcs.
Well, the end of One Punch Man in the manga comes after a series of intense battles and character developments. It ties up many loose ends but leaves some room for interpretation. I'd recommend reading it yourself to fully experience the conclusion.
It ends at a specific chapter, but I can't recall exactly off the top of my head. You might want to check online manga forums or dedicated One Punch Man fan sites for the precise chapter.