The Valt system was an inhabited planetary star system in the Beta Quadrant. The system contained the inhabited planet Valt Minor, the homeworld of the Valtese. (TNG: "The Perfect Mate")
In 2256, this system's location was labeled on the star chart "Alpha/Beta Quadrant Overview" in the ready room aboard the USS Discovery. It was located in the territory of the Klingon Empire. (TNG: "The Perfect Mate"; DIS: "Magic to Make the Sanest Man Go Mad", "The War Without, The War Within")
A year later, its location was labeled on the star chart showing the trajectory of Lieutenant Spock's shuttle. (DIS: "An Obol for Charon")
In 2399, the system's location was labeled on a Federation star chart that was in Fleet Admiral Kirsten Clancy's office at Starfleet Headquarters. It was located in neutral space. (PIC: "Maps and Legends")
In 3189, the location of the Valt system was denoted on a holographic star chart of the galaxy at Federation Headquarters. (DIS: "Die Trying")