Brock's Gym is located in pewter city. He owns rock type Pokemon so use a water or fight type Pokemon in your battle.
go to cerulian city
Pewter city
I believe one of Professor Oak's aides gives you them after you beat Brock and are exiting the city to the east.
Battle brock
in firered/leafgreen there is no city by that name
There is no "Pal Park" in Pokemon Firered Version.
Brock isn't in Diamond and Pearl. He is in another game but i forgot which one it was. Hes in Pokemon LeafGreen and FireRed as the frist gym leader and there he got geodude and onix
a city
You can retrieve the Boulder Badge from Brock, the Gym Leader of Pewter City however you can only battle Brock as a Gym Leader in games such as Pokémon Red, Pokémon Blue, Pokémon Yellow, Pokémon Gold, Pokémon Silver, Pokémon Crystal, Pokemon FireRed, Pokemon LeafGreen, Pokémon HeartGold and SoulSilver.
You have to defeat Brock in the Pewter Gym and get the badge. I know it's annoying.
In Pewter City.
cerulean city