New Memphis was an Earth colony, established prior to 2479 (most probably in the middle of 24th century). It was well known for its large spaceport, known as Elvis the King Spaceport and its largest settlement, New Memphis.
History
Before Human Colonisation
Before humanity arrived, New Memphis was an uninhabited planetoid of little interest to anyone. However, the government of Earth soon showed interest in the planetoid because it was close to a major hyperspace nexus point. Thus, a refueling station was established to assist the traffic crossing that point, coming from at least a hundred different star systems.
Growth
Over the course of a hundred years, the refuelling station became more permanent, becoming the Elvis the King Spaceport. Soon, a permanent population began to establish itself and the city state of New Memphis was established outside of the spaceport. By 2479, the spaceport had ten terminals at full working capacity and a further two shut down pending further notice. A thirteenth terminal had already begun construction. The Doctor visited this planet in 2487. (NSA: Judgement of the Judoon)