Is the underground in goldenrod only place you can get haircuts Pokemon crystal?

You are correct! In Pokémon Crystal, the underground in Goldenrod City is the only place you can get haircuts.

Here's why:

* The Salon: In the underground, there's a hidden "salon" where a friendly Pokémon Trainer will style your character's hair for free.

* No Other Options: There are no other places in the game where you can get haircuts.

So, if you're looking for a new 'do in your Crystal adventure, make sure to head down to the Goldenrod underground!