Benthos IV was the inhabited fourth planet in its star system.
Osyraa, leader of the Emerald Chain, once used a ploy to gain entry through the shields on Benthos IV, whereupon she destroyed the presidential palace. Cleveland Booker recounted this incident to Michael Burnham in 3189 when Osyraa, on the USS Discovery, was allowed through the distortion field protecting Federation Headquarters. (DIS: "There Is A Tide...")
This may be the same planet that the impostor "Steth" claimed to be from in "Vis à Vis", which they named as Benthos and described as the fourth planet of the Benthan system.