The Mari homeworld was an inhabited Delta Quadrant planet, and the homeworld of the Mari species. It contained at least one city.
The Mari were a telepathic, humanoid species. Until the mid-24th century, the Mari homeworld was a violent place. The Mari's telepathic powers allowed them to send violent thoughts to each other. (VOY: "Random Thoughts")
According to the Star Trek: Star Charts (p. 88), the Mari homeworld was located in the Mari system. The Mari system was located in non-aligned space between the Krenim Imperium and the B'omar Sovereignty. This system was a binary star system with a pair of class A stars. The USS Voyager visited this system on stardate 51367.