Yitheeth existed as an oceanic planet within the Yinchorri system. The Yinchorri constructed at least one urban center on the planet's terrain. The Ambush on Yitheeth occurred there in 33 BBY amidst the Yinchorri Uprising. Ninety-three percent of the surface was covered by shallow bodies of water.
Contrary to what is stated in The New Essential Chronology, which identifies Yitheeth as a moon orbiting Yinchorr, Jedi Council: Acts of War explicitly establishes it as a planet.