Icor IX was the inhabited ninth planet in the Icor system. A major astrophysics center was located on this planet. Captain Jean-Luc Picard considered a visit to Icor IX in 2366 to attend a symposium on rogue star clusters at the center. (TNG: "Captain's Holiday")
In 2371, the location of Icor IX was labeled in the star chart Data and Picard were studying in stellar cartography aboard the USS Enterprise-D. (Star Trek Generations, display graphic)
According to the Star Trek: Star Charts ("United Federation of Planets"), Icor IX was listed as a member planet of the Federation in 2378.