The planet possessed few, if any, natural resources and was inhospitable to most lifeforms except its indigenous Barzans, a humanoid species. The planet was governed by the Barzanian Planetary Republic.
In 2366, the Federation starship USS Enterprise-D hosted the negotiations in orbit of Barzan II for the right to control the newly-discovered Barzan wormhole. It soon became clear that the other end of the wormhole was not stable, and its possible use as a resource vanished, although the Chrysalians had already purchased the rights by that time. (TNG: "The Price"; VOY: "False Profits")
Since the 27th century, Federation members rotated responsibility for crewing the Federation seed vault. In 3189, Barzan held responsibility for the USS Tikhov, crewed by Dr. Attis and his family. Commander Nhan would later take on the responsibility, with the intention of returning Attis' family to Barzan II for burial. (DIS: "Die Trying")
"BAR-zan" was the pronunciation for this planet from the script pronunciation guide for "The Price".
The planet model for Barzan II was first used for 'aucdet IX. (TNG: "The Child"). It was used again for Gagarin IV and Galorndon Core. (TNG: "Unnatural Selection", "The Enemy") It was used later for Jouret IV and Bilana III. (TNG: "The Best of Both Worlds", "New Ground") For its use as Barzan II, the model had a green color.
It was stated by Harry Kim in the episode "False Profits" that one terminus of the Barzan wormhole was fixed in the Alpha Quadrant.