In Isla Nublar, there was at least one open Brachiosaurus pen on the island. The pen was situated just moments away from the Jurassic Park main gate, and was moderately forested. There was also a river flowing past as well, and the track for the electric jeeps ran along the side of it. There were at least six individuals in the pen.
The Brachiosaurus pen was the first pen that Hammond showed his guests on the tour. The sight of these majestic creatures was enough to instantly convince most of the group that Jurassic Park was safe, fun, and enjoyable.