House Atreides resides on Planet Caladan, the third planet of Delta Pavonis.  It was ruled by Duke Leto I until the treachery of the Emperor, Shaddam IV, and House Corrino caused the death of the Duke and the succession of the House into the hands of Paul, and subsequently, the God Emperor.

House Corrino once ruled the Empire from the planet Kaitain.  After Paul Atreides became Emperor of the Padishah Imperium, the throne was moved to Arrakis.  The House Corrino is closely related to House Atreides, and the two were once allied.  House Corrino's existence is, in part, due to the heroics of House Atreides at the Battle of Corrin, in 88 B.G.

House Harkonnen inhabits Giedi Prime, the Ophiuchi B.  Their world is a putrid place, soaked in oil from industry and environmental abuse.  It appears as a black world, and has very little plant life at all.  They are staunch enemies of House Atreides.