Where do you find a Pikachu in diamond?

You can't find a Pikachu in Pokemon Diamond! Pikachu is a non-native Pokemon to the Sinnoh region, which is where Pokemon Diamond takes place.

While there are ways to obtain Pikachu in Diamond, it's not a wild encounter:

* Trading: You can trade for a Pikachu with someone who has one from a different game.

* Events: Occasionally, Nintendo would distribute Pikachu through events, but these are usually limited-time offers.

If you want to experience catching a Pikachu in a Pokemon game, you'll need to play a game where it is native, such as Pokemon Yellow, Pokemon Red, Pokemon Blue, or Pokemon FireRed/LeafGreen.