What is the name of the second island where dinosaurs were bred?

The second island where dinosaurs were bred is Isla Sorna, also known as Site B. InGen used the island as its main research and production facility before transporting selected dinosaurs to Isla Nublar.

Unlike Isla Nublar, which was developed as the public-facing Jurassic Park theme park, Isla Sorna housed laboratories, hatcheries, and other facilities used to create and raise the animals. The island therefore functioned as the behind-the-scenes source of the park’s dinosaur population.

Isla Sorna is part of the fictional Las Cinco Muertes island chain. It is much larger than Isla Nublar and became the main setting for The Lost World: Jurassic Park and Jurassic Park III. After InGen abandoned the site, many dinosaurs lived and reproduced there without human control.

The island’s name is a common mix-up because Isla Nublar is the location most associated with the original park. Isla Matanceros and Isla Muerta are also names from the wider franchise, but they are not the canonical Site B where InGen bred its dinosaurs.