Tartarus is the Tok'ra name for a planet on the edge of Goa'uld controlled space that was thought to be unoccupied. When a Kull Warrior was successfully captured by SG-1 and interrogated using a modified memory recall device, he revealed Tartarus to be his home planet, and Tok'ra intelligence confirmed that Anubis had established a base on the planet.
Tartarus has a rugged mountainous terrain with steep chasms and caves and an elevated causeway leading to the anti-gravity structure that served as Anubis's secret base. It was there that Thoth supervised the breeding of symbiote drones for the creation of Anubis's army of thousands of Kull Warriors. Although a formidable sensor array defended the planet, and the stargate was protected by a powerful force field, SG-1 was able to infiltrate the base and to use explosives to destroy the Goa'uld queen used for breeding as well as many of the laboratory facilities.
Following the defeat of the Replicators, intelligence indicated that Anubis was marshalling the remaining Kull Warriors on Tartarus, and the Rebel Jaffa united and prepared a preemptive strike on the planet. However, the Rebel forces found Tartarus was deserted, and they learned that Anubis had used false intelligence to lure them away from Dakara so that he could reclaim the temple there.
Cross Reference: Anubis, Kull Warrior, Radioactive Isotope, Thoth
Episode Reference: Evolution, Threads
Stargate Coordinates: 33-28-23-26-16-31