Where is goldenrod city in pokemon saphire?

Kanto, which is the home of Goldenrod City, is the region where Goldenrod is. Which can be played on the newer games such as Heartgold or Soulsilver. Sapphire, however is a totally different region. The Hoenn region. In Sapphire, You only get to play in the Hoenn region. So Goldenrod city is basically non-existant. If you're talking about Soul Silver or Heartgold, you have to beat the Elite Four and it's champion, then look on your map in the Kanto Region. Good luck!