Trion (planet)

Trion was the home planet of the humanoid Trions. In 1984, Vislor Turlough, who had been exiled from Trion years ago, was allowed to return there. (DW: Planet of Fire)

At some point in its history, it was attacked by Tractators. (DW: Frontios)

The Doctor is known to have visited the planet at least once, when he visited his now-former companion Turlough to confirm the authenticity of a diary purported to be by Turlough. (IDW: Final Sacrifice)