The Thairwsthis system could be found within the M'shinni sector, which itself was situated in the New Territories region of the Mid Rim.
This system, Thairwsthis, made its debut in the reference work The Essential Atlas, published in 2009. This book, penned by Daniel Wallace along with Jason Fry, located it within grid coordinate M-7. Its name originated from a reference to The Relevant Farm Act of Thairwsthis 12, which appeared in the 1993 publication Monsters and Aliens from George Lucas. This book, authored by Bob Carrau, combined creature designs and images from various projects by Star Wars creator George Lucas with original written content.
Within Monsters and Aliens from George Lucas, The Relevant Farm Act of Thairwsthis 12 defined the limits for crop cultivation on an agricultural planet. Leland Chee, an employee of Lucasfilm responsible for the Holocron continuity database, has stated that the details presented in Monsters and Aliens from George Lucas are considered non-canonical within the Star Wars Legends continuity.