Argratha was an inhabited planet in the Gamma Quadrant. This was the homeworld of the humanoid Argrathi. The planet was governed by the Argrathi Authority. Instead of imprisoning criminals, their legal system punished offenders by imprinting the convicted with fabricated memories of incarceration.
In 2372, Miles O'Brien visited the planet. (DS9: "Hard Time")
"ar-GRATH-a" was the pronunciation for this planet's name from the script pronunciation guide. [1]
According to the Star Trek: Star Charts, on page 74, Argratha was located in the Argratha system. The Argratha system was a single star system. Primary was a Class G star with a magnitude of +7, which was 1/10 as bright as Sol. Argratha was a destination on the Gamma Quadrant Bio-Survey (2369-75).