When a spell is countered, it is placed into its owner's graveyard. This is the standard rule: a countered spell is removed from the stack and put into the graveyard (CR 701.5a). It does not resolve, but it still ends up in the graveyard just as it would if it had resolved and was a non-permanent spell.
There is one important exception: some spells have a replacement effect that changes where they go when countered. The most famous example is spells with the ability 'If this spell would be countered, exile it instead.' In those cases, the card goes to exile rather than the graveyard (CR 701.5b).
Additionally, some counterspells themselves specify a different destination. For example, Remand says 'return it to its owner's hand' — so the countered spell goes to the hand instead of the graveyard. Always read both the counterspell and the countered spell for any replacement effects.
Concrete example: Your opponent casts Lightning Bolt. You cast Counterspell. Lightning Bolt is countered and goes to your opponent's graveyard — it never dealt damage, but it is now in the graveyard and could later be retrieved by cards like Recoup.
Key rules to remember: CR 701.5a covers the basic 'countered → graveyard' rule, and CR 614.1 covers replacement effects that can redirect a countered spell elsewhere.
Unofficial fan resource — not affiliated with or endorsed by Wizards of the Coast. Answers are AI-generated estimates grounded in the Comprehensive Rules and are not a substitute for an official judge. Verify anything match-critical.