Solosos IV is the fourth planet in the Solosos system, located near the border of the Cardassian Union.

The planet was colonized in the 22nd century by a group of Native Americans. Among them was a man who was an ancestor of Kolopak, who decided to settle there with his family. Kolopak's family lived on Solosos IV until the year 2290. Kolopak's father and mother moved back to Earth with their son after becoming disillusioned with their tribe's new rules. However, after having a near-death experience in a shuttle accident in 2304 on Earth, Kolopak moved to Solosos IV and began a new spiritual life there. Years later, in 2329, his son Chakotay was born on this planet. Solosos IV became the Maquis' lead base once Chakotay resigned from Starfleet and joined the resistance. The planet's Human population was wiped out by Jem'Hadar in 2373 and the Maquis ceased to exist. In 2375, Solosos IV was changed to become a Dominion supply facility for damaged Jem'Hadar battleships and other needed supplies. After the war was won later that year, the Dominion returned control of the planet back to the Federation.