The Vaadwaur homeworld was an unhabited planet in the Delta Quadrant, formerly home to the Vaadwaur species. In the late 15th century, the population of the planet was six billion.
In 1484, the planet was the site of the last stand of the Vaadwaur before their defeat by the Turei and their allies. The planet was the subject of a massive orbital bombardment by plasma bombs, which wiped out all life on the surface and caused a nuclear winter that rendered the planet uninhabitable for centuries. A battalion and their families, approximately six hundred Vaadwaur, managed to survive in stasis underground, along with ships, land vehicles, and weapons.
The surviving Vaadwaur were re-awakened by the crew of the USS Voyager 892 years later. At that time, the planet's atmosphere was still heavily contaminated with gamma radiation and charged with radiogenic particles at 3,000 isorems. (VOY: "Dragon's Teeth")
According to the Star Trek: Star Charts (p. 92), Vaadwaur was located in the Vaadwaur system. This system, visited by Voyager on stardate 53167, had a K-class primary.
In Star Trek Online, this planet is called Vaadwaur Prime and is the capital of the reborn Vaadwaur Supremacy.