System L-374 was an uninhabited planetary system with four planets that was located somewhere in the Alpha or Beta Quadrant. This system, and the L-370 system, were located in the same sector. The Rigel system was close to this system.
The system was attacked by the "planet killer" in 2267. It had four terrestrial worlds that were charted prior to the attack; the surface temperature of one inner planet was that of molten lead and another had an atmosphere poisonous to Humans; the two outer planets were consumed as fuel by the machine before it could be destroyed by the starships USS Enterprise and USS Constellation. (TOS: "The Doomsday Machine")