You can find him in the lower regions of the desert
I don't think you can get regirock in pokemon ruby.
in ruby there's groudon, raquaza, regirock, (if you consider it a lengendary) regice, and regirock
to get regirock in Pokemon platinum, you have to upload it from ruby, Sapphire, or emerald.
You can only get Regirock by transferring a Regirock from Pokemon Ruby, Saphire, or Emerald to the Pal Park I believe.
You'll have to trade Regirock from Ruby, Sapphire, or Emerald.You get a regeirock by trading it from ruby sapphire or emerald. that's how you get it to fire red.
In Diamond you can't catch Regirock, you have to migrate it from Pokemon Ruby, Sapphire, or Emerald.
You cannot get Regirock in Diamond without migrating one from Ruby, Sapphire or Emerald.
Regirock
you can not get regigigas! but you can catch regice, regirock, registel.
doesn't matter.
you can gain regirock by getting the national pokedex the going to pal park then transferring it from Pokemon ruby or emerald then cath it
To get a Regirock, Regice or Registeel you have to migrate one from Ruby, Sapphire, Emerald, Leaf Green or Fire Red.