Kala'uun functioned as a starport situated on the planet called Ryloth.
During the time of the Ryloth Insurgency which occurred after the Clone Wars, TriNebulon News broadcasted from Kala'uun that Cham Syndulla, representing the Free Ryloth Movement, declared responsibility for the explosion of a reservoir. This explosion resulted in the destruction of an Imperial hovertrain due to flooding.
Sometime before the destruction that befell the planet Alderaan, the smuggler known as Han Solo paid a visit to Kala'uun. While there, he began a relationship with a Twi'lek bartender whose name was Hellene.
Kala'uun was initially presented as a city located on the planet Ryloth within the Star Wars Legends short story titled "Big Quince." This story was penned by Peter M. Schweighofer and featured in Star Wars Adventure Journal 2 back in 1994. While its precise location remained unconfirmed, the existence of the city was established as canon through A New Hope: The Princess, the Scoundrel, and the Farm Boy. This adaptation of Star Wars: Episode IV A New Hope was authored by Alexandra Bracken and released during 2015.