The New World refers to the second half of the Grand Line. It is located between West and North Blue, and Fish-Man Island and the other side of Reverse Mountain. The only known people to have fully explored it are Gol D. Roger and his crew.
Islands within the New World
The New World is also the primary geographical setting for the network known as the Underworld, an underground network of black market connections and illicit dealings which are beyond the World Government's control.