Ithor was the fourth planet located in Ottega system of the Mid Rim. One of the oldest members of the Galactic Republic, it was a planet full of lush life, and the planet's surface had not a touch of civilization on it. The Ithorians themselves, otherwise known as "Hammerheads," built great floating cities that did not harm the surface, which they considered to be sacred. Entry upon the surface was forbidden, unless one stayed there permanently. Some Ithorians such as the Oracle were compelled to go down to the planet surface, however, as they "heard the call" of Mother Jungle, the Ithorian religion's personification of Ithor's world-spanning jungle. The surface of the planet of Ithor played host to numerous plants, including the bafforr tree, which possessed telepathic capabilities. The planet contained andurite stone, and every three Ithorian years was the center of the Time of Meeting. The planet had many moons in its night sky.
Ithor joined the Galactic Republic prior to 8000 BBY. In 3963 BBY, when Republic fleet encountered a Mandalorian raiding force in an asteroid field near Ottega system, Dace Golliard predicted they would attack Ithor next, although it turned out to be a ruse set up by Zayne Carrick and Cassus Fett to capture Golliard. In 439 BBY, scientists attempted to bond the telepathic capabilities of the bafforr tree with another, more vicious tree on the planet surface. The result was a new parasitic life form named "Spore," but its parasitic hostility forced the Ithorians to lock it away in an asteroid 300 BBY. It was long afterwards discovered by miners. In 19 BBY, Grand Master Yoda of the Jedi Order, was reported dead in an incident on Ithor.
Sometime before the Battle of Yavin, Ithor came under siege by the Galactic Empire, which demanded access to Ithorian agricultural techniques and technology in an attempt to locate biotech for military applications. Lead by Captain Alima he threatened the Ithorians with the destruction of their sentient forests, the Cathor Hills. However the Empire was ousted from the planet through a deal formulated by Momaw Nadon, where he bargained with the Empire to reveal the secrets of the Ithorians' technology and agricultural ceremonies, in return for the protection of their 'mother jungle'.
Sometime after the Battle of Yavin, the Galactic Empire planned to attack the planet. The Rebel Alliance heard of these plans prior to the attack and dispatched Han Solo to rescue a group of Ithorians wishing to evacuate. Just a few minutes before the attack, Han and his co-pilot Chewbacca were able to rescue the Ithorians. A small battle raged afterwards, with many TIE Fighters. Han and Chewbacca managed to dodge space slugs in a nearby asteroid field and place the Ithorians on Bimmisaari.