Judoonia was the home planet of the Judoon. It had mountains 1,000 miles high. (AUDIO: Judoon in Chains) Nukeball was forbidden on Judoonia to make sure that the population was not wiped out. (PROSE: The Coming of the Terraphiles)
After an ordeal with the Paradoxica, the Eighth Doctor dropped Kon Po off north of the mountains on Judoonia. A settlement could be found half a klik away from where they landed. The Doctor then found that time had been derailed on Judoonia in the Divine Intervention timeline. (AUDIO: Patience)
In an alternate timeline, the inhabitants of Judoonia had been mostly converted into Cyber-Judoon by 2493. (COMIC: Assimilation2)