Altair IV

Altair IV is the fourth planet in the Altair system, orbiting the star named Altair. It is home to a Federation population.

Darien Wallace was born on this planet. (TNG: "Eye of the Beholder")

In 2371, a resident of this world, one Doctor Henri Roget of the Central Hospital of Altair IV, was awarded the prestigious Carrington Award for his work in the field of medicine. (DS9: "Prophet Motive")

It was never directly referred to as a Federation world. Altair IV was the alien world featured in the pre-Star Trek film Forbidden Planet.