A world in the Arcadian star system whose main industry is heavy metal mining. One of the cities there has multiple low buildings, as well as a handful of multi-story spires. The miners there are a mixture of humans, brown-skinned bipedal ursinoids, and brown-faced amphibious-looking humanoids. Motherlode does not recognize Federation law. In 2269 (stardate 4978.5), the crew of the U.S.S. Enterprise visits the world to retrieve huckster Harry Mudd, who is attempting to sell a fake love potion to the miners.