The Trench, unofficially referred to as The Pig Trough, was an anomalous geographic feature on Folor, the moon of Commenor. This fissure ran several thousand kilometers northeast of the New Republic Folor Base, then northwest and continued an even longer distance. It was unknown how the Pig Trough came to exist, due to Folor's stable tectonics.
New Republic pilots, particularly the A-wing, X-wing, and Y-wing trainees at Folor Base, used the Pig Trough for practice runs. The deep crevice in the moon's surface with narrow, winding sections gave them a challenge in their fast-moving fighter craft. It was designated a gunnery and bombing range, and when other fighter fighters were practicing in the satellite field orbiting Folor, Y-Wing squadrons dropped charges over the canyon.
When Admiral Apwar Trigit attacked Folor Base in 8 ABY, Republic Flight officers Kell Tainer and Hohass Ekwesh of Wraith Squadron and Dorset Konnair and Tetengo Noor of Blue Squadron flew up the Pig Trough (unofficially racing their differing fighter craft along the way) to scout out the Implacable. They also managed to draw the Imperial Star Destroyer to their position as a diversion, using their familiarity with piloting the Pig Trough to have a margin of cover as they flew back to their squadrons, running the gauntlet of Trigit's turbolasers.
Wraith and Blue Squadrons were also able to hide in the Pig Trough as they traveled from Folor Base itself to their engagement zone with the Implacable's TIE Interceptors.