The Jedi Archives located on Ossus, a repository of knowledge at the Ossus Academy, was smaller in scale compared to the grand collection housed within the Jedi Temple on Coruscant. Just like its larger counterpart, the Archives were consistently accessible, providing all Jedi with a source of information whenever needed.
Following the destruction of the Jedi Praxeum on Yavin 4 and the conclusion of the Yuuzhan Vong War, the New Jedi Order made a move to Ossus. It was there that Jedi historian Tionne Solusar amassed a substantial collection of both manuscripts and holocrons that were salvaged from the scattered remnants of the Old Jedi Order's belongings.
Later, during the Galactic Civil War, after the New Republic successfully reclaimed Coruscant, Master Tionne enriched the Archives with historical data pertaining to the Rebel Alliance. She discovered the original founding documents of the Jedi Order within the Sacred spire and uncovered a great deal of information from Palpatine's hidden treasure chambers, enabling her to rapidly expand the collection. Tionne also acquired the Great Holocron, a significant find for the Jedi Order. To maintain control over the accumulated treasures and to facilitate thorough research and updates, she relocated the information from Coruscant to Yavin 4 and eventually to Ossus.
When the Coruscant Temple underwent reconstruction, Tionne transported a significant portion of the Archives' holdings back to the Galactic capital. Given her involvement with the Ossus academy, she officially established a branch of the Archives there. This branch served as an educational resource for Younglings and aided in research endeavors, housing a comprehensive collection of galactic history and political information. However, it intentionally omitted detailed records of the Sith or their technology.
During the Galactic Alliance Guard invasion, Dark Jedi Alema Rar managed to infiltrate the Archives, only to be disappointed by the lack of information concerning her newly acquired acquisition.
When the academy was evacuated for the safety of the Jedi's secret Endor base, the archives were emptied of their contents, and the materials were removed from the planet. While the academy remained closed and abandoned, Master Solusar continued her archival work from the larger facility located on Coruscant.