Neubilia Prime was the inhabited prime planet in the Neubilia system. This planet was once visited by the father of Travis Mayweather. Mayweather said that the tribal elders on Neubilia could challenge visitors to a duel if "you look at them the wrong way." Mayweather's father, who captained the Earth Cargo Ship Horizon, was challenged to such a duel. Mayweather suggested to Hoshi Sato that his father accepted the challenge and won the battle, rather than look for a loophole to get out of it. This inspired Hoshi and Travis to find a way for Jonathan Archer to defeat Andorian Commander Shran in a traditional Andorian honor duel (the Ushaan) without killing him. (ENT: "United")
Neubilia Prime was named for high school teacher Karyn Newbill, the girlfriend of Enterprise producer Mike Sussman. The DVD closed captioning spelled the name of this planet as "Nobelia Prime," however "Neubilia" was the spelling used in the script.
According to ENT: "Two Days and Two Nights", prior to 2151, Earth ships had been operating within 90 light years of the Sol system. In that year, the Enterprise became the first ship to travel further than this distance. With the planet probably being visited before 2151, Neubilia Prime was presumably located within this range.