Selonia was an industrial world, comprising many small islands surrounded by a global ocean. However, to circumvent this obstacle, the Selonians dug an elaborate network of tunnels under the planetary surface, thus facilitating contact among their peoples. The planet's oceans were rumored to be the habitat of sea monsters, since it was said that only Selonia's oceans were large enough to accommodate these creatures.
Selonian "dens" and tunnels ran through much of the planet's crust and mantle, while orbital shipyards operated above. Most of the vessels produced over Selonia were constructed for use within the Corellian system and, since Selonians generally had little interest in exploring further, were not fitted with hyperdrives.
One of the most striking features of the planet was a volcanic mountain range known as the Cloudland Peaks, said to rise so high that their tops were obscured.
Selonia was close enough to the planet Corellia that it was easily recognizable by most Corellians among the many stars of the nighttime sky.
The Selonian species lived in hives created around a fertile female.
It was believed that the Celestials moved the planet into Corell's orbit, along with four other planets, facilitated by planetary repulsors and Centerpoint Station. It is unknown whether Selonians were indigenous to the planet, or whether they were transplanted there by the Celestials. It is known that the planet was annexed by the Infinite Empire in 30,000 BBY.
Selonia was the site of a victory for the Confederacy of Independent Systems over the Galactic Republic during the early stages of the Clone Wars.
During the Yuuzhan Vong War, the Pride of Selonia was named after the world. During the Second Galactic Civil War in 40 ABY, Selonia was blockaded by the Galactic Alliance. By around 130 ABY, the planet was orbited by the Selonian Shipyards.