The closest planet to the Columus system's star, Columus consists of a wide variety of terrains. Saltwater oceans, which experience a distinct lack of tidal activity, comprise 11% of the planet's total surface area. The lithosphere of Columus is broken up into only two tectonic plates; consequently, there is only one mountain range on the entire planet. These mountains are largely unexplored and may be the habitat of thousands of undiscovered animals and plants.

Columus is the most hospitable world in the Columus system. The atmosphere is primarily made up of nitrogen, oxygen, and xenon, with traces of argon and carbon dioxide. The high levels of xenon make the planet unique in the galaxy. Interestingly, the amount of xenon results in many species gaining an improved pain threshold on the planet's surface where xenon is most concentrated. This does not mean, however, that one is less susceptible to injury on Columus.

With an almost perfectly circular orbit, Columus is outstandingly stable and perfect for the evolution of life; an axial tilt of 29.5° away from the perpendicular also adds to the planet's habitability. As a result, Columus is home to millions of indigenous species, none of which can be considered sentient. According to the world's flimsy fossil record, life first appeared on the planet approximately two billion years ago. Primates, gorging themselves on "giggle berries", are commonplace in the dense jungles and forests of Columus.

A handful of settlers originally colonized Columus during the Clone Wars while performing research into the benefits of the planet's high-xenon atmosphere. Since then, immigrants and refugees have flocked to the planet to avoid conflict closer to the center of the galaxy, and the planet is considered an ideal hiding place for anybody on the run.