Huh... sunshine, green grass, gentle rivers, no mutant Geo's. We sure this is a Jedi world?
—Zhavi, after setting foot on Shimka's Well for the first time.
Shimka's Well, once known simply as the Well and later as the Lost Fortress of Shimka, was a remote, tropical waterworld situated at the heart of the Rose Nebula in the Outer Rim Territories. It was a small, idyllic world with a solid core that was once inhabited by the Zeffo, who were believed to have been responsible for the creation of the artificial waterfalls surrounding the island that would one day be referred to as the Well and, presumably, inspired the naming of the site, though evidence was never discovered to confirm this.
Long after the Zeffo left the planet, Shimka's Well was chosen by Jedi artisan Master Shimka to host a hidden research outpost, due to its agreeable conditions, remoteness and the secrecy provided by the surrounding nebula, which blinded sensors, making safe navigation of the are almost impossible and ensuring it would not be found during a period of darkness Master Shimka had foreseen. Shimka and his fellow artisans were the only beings who knew the location of the Well and after their deaths the planet was lost to history, whereupon it came to be regarded as a semi-mythical location and finally received the name Shimka's Well, or in some tales the "Lost Fortress" of Shimka, after the errant Jedi Master himself.
Using information discovered during the rediscovery of Ahch-To, Aaellu Lambert led a privately funded expedition to find the so-called "Lost Fortress" in 43 ATC, locating the tropical world alongside Jedi Masters Oteg, Odé and Zhavi Waverunner, the latter accompanied by her wife Isla Waverunner. This expedition continued for two years, funded by Aaellu's husband, Governor Benjamin Lambert, until the so-called Waverunner Exodus in 45 ATC, when Zhavi Waverunner publicly denounced the Jedi Order and (alongside members of the Republic Strategic Information Service's Strategic Asset Reassignment Bureau) defected from the Galactic Republic to settle on the planet she had helped to rediscover, claiming it as an independent world and opening the Shimka's Well Enclave with herself as its headteacher.
Supported by Lambert's government on Farrow, Shimka's Well rapidly grew in size over the decades that followed and became a respected independent world with cordial relations with the Galactic Republic, making its mark on the galaxy through the actions of its defense force, the Advanced Strategic Operations Service, in particular the commandos, who helped deliver several severe blows to the fractured remnants of the Sith Empire which helped to smooth over previous tensions between the colony and the Galactic Republic. Such was its growth that the colony had to be expanded underwater in 54 ATC, using hydrostatic field technology acquired through diplomatic work with the Gungans of Otoh Bonso. At an unknown point, Shimka's Well also began hosting the annual Wisdom Week event, a period when various Force using organizations were invited to visit, learn and share with one another in a safe environment, with the intention of creating greater understanding between the separate groups.
In 66 ATC, Shimka's Well was attacked by the Hutt businessman Gaddim, who – under the direction of the extra-galactic Zhaelor Vong – sent a small suicide fleet to bomb the planet. While prepared for the attack, the planet nonetheless came under threat when two bomb-laden starfighters managed to breach the atmosphere before the planetary shield could be raised. However, thanks to localized shielding protecting the major points of interest, the Mesa Temple – the target of the attack – was spared destruction, although Temple Mesa, upon which it was located, was still leveled by the blast.
Following the defeat of Darth Desolous in 196 ATC, Meetra Waverunner experienced a vision of the Clone Wars, the execution of Order 66 and the subsequent rise of the Galactic Empire. Though she knew the threat she had foreseen was far into the future, she began making preparations to ensure the safety of Shimka's Well and the preservation of the knowledge therein, just as Master Shimka had centuries prior. Meetra personally infiltrated the Jedi Temple to erase the location of Shimka's Well from the Jedi Archives in the immediate aftermath of the battle of Yaga Minor.
At some point, Meetra's plan to secure the survival of Shimka's Well was successful, as the planet was once again considered little more than a legend by the time of the New Sith Wars and thus, when the Clone Wars ended and Order 66 was given, the Shimkan Jedi Order survived. In 0 BBY, sensing the destruction of Alderaan, the leadership of Shimka's Well finally brought the planet out of hiding and entered the Galactic Civil War, fulfilling a prophecy left by Meetra Waverunner that predicted the planet's reemergence.