Southern Archipelago
The Southern Archipelago was a fictional archipelago located on the planet Ardani, created by Thaddeus Troi-Riker. The archipelago had a tropical climate and were covered by jungles.
This was the home of the Ukelu.
Even after the death of her son, Deanna Troi kept the notes about the cultures of Ardani, one of which had detailed information about the Ukelu, in which this location was mentioned. (PIC: "Nepenthe")
In background notes Michael Chabon provided the props department and later published online, Troi-Riker based the islands of the Ukelu Empire on the climate of Betazed. [1]