Newtrogic High Zone, previously known as Carnival Island, is the main setting of Knuckles' Chaotix. After completing introduction level Isolated Island, Newtrogic High Zone becomes the hub world of the game, where the player can choose the combi partner (person who is trapped in a Combi Catcher) and level.
In the English storyline, it is located on Carnival Island, which Knuckles patrols before its grand opening day—though Dr. Robotnik sets his sights on its "Power Emerald" which supplies electricity. In the Japanese storyline, Dr. Eggman discovered that an unnamed island rose from the sea, and built Newtrogic High Zone on the island after he discovered the Special Ring, a ring that on the inner part has an inscription in the ancient language of Knuckles' people. The Chaotix Crew also arrived of their own accord: Vector the Crocodile believes the island's rise is a miracle of God, Espio the Chameleon goes to investigate, Charmy Bee (or "the fastest insect in the world") travels to the island to search for a new flower, Mighty the Armadillo happened to come across the island while adventuring, and Knuckles the Echidna comes because he noticed and fears it is connected to the Floating Island. Heavy and Bomb defected from Robotnik and decided to help the Chaotix Crew. After the Chaotix Crew (except Knuckles) arrive on the island, they are captured in Robotnik's Combi Confiner. After Knuckles started to explore the island, he came across Espio, who was trapped in one of the machines. Using the power of his ring, he freed Espio and tried to obtain the Chaos Rings and stop Robotnik.
After completing all the "attractions", Metal Sonic comes out and fights the Chaotix Crew. After being defeated, he flees to Robotnik, who escapes as the final boss suddenly appears. But despite his great size and power, he is defeated. If the player manages to collect all the Chaos Rings, the island will presumably be restored, and even Sonic and Tails visit on the Tornado. If the player fails, the final boss will appear, overlooking a burning city (likey Newtrogic High Zone).
- Botanic Base: The island's most natural attraction is this giant greenhouse, filled with oddly geometric trees, and a jungle of hostile flora.
- Speed Slider: A roller coaster reminiscent of Casino Night and Carnival Night Zone, Speed Slider is the fastest attraction in Knuckles' Chaotix. The level moves all the way to a confrontation with Dr. Robotnik on his carousel.
- Amazing Arena: At the start of this stage, the player is in the dark, but once the light switch is hit, Amazing Arena turns bright and colorful. If the player fails to locate it, the stage starts all over again.
- Techno Tower: A futuristic-styled tower that the player must climb. In Level 5, the player can hop on a drill machine that burrows through solid walls.
- Marina Madness: A cruise-themed attraction with, curiously, no water. The player must jump from ship to ship to complete this level while dodging flying fish and sailing stingrays.
- World Entrance: Between each stage the player visits the World Entrance. Here, one can choose to end the game, select a new partner, and/or choose a new stage. It is also home to the final boss battles.
- The artwork of Newtrogic High Zone (see above the article) is seen at the Sega intro in earlier prototypes of Knuckles' Chaotix, but it has been later replaced with normal space background in final version.