Herilia, designated P4X-552 by the Tau'ri, was a planet in Milky Way galaxy which has a Stargate. Herilia is farther from its sun than Earth, but this lack of sunlight is made up for by numerous greenhouse gas emissions which makes it a habitable, but dark, world. The Herilians of Celtic descent who the Goa'uld Diancecht brought from Earth have grown accustomed to this darkness, but offworld visitors would be disoriented by it. Crotaine was a large city located about an hour drive from an SGC base on the planet. Diancecht was overthrown, but returned later and posed as a Herilian bureaucrat to manipulate the Herilian government without their knowledge. (RPG: "The Herilian Agenda")