Site B/Isla Sorna and Isla Nublar/Jurassic Park
Isla Sorna, alias Site B, is one island of the group The Five Deaths. "Isla Sorna" means Sarcasm Island in Spanish. The research station of InGen, which created dinosaurus, was located on this island. It is the place where most of the movies, books and games about Jurassic Park take place.
Site B is where they made the dinosaurs, as explained in the second Jurassic Park book. You see from stage to stage but what about in between. Site B is where everything else that they didn't want to display happened. I recommend you read the second book by Michael Crichton if you haven't and like Jurassic Park or would like this further explained.
Different versions of Isla Sorna exist in the different Jurassic Park canons: