L-374 was a star system with four planets. This system was located in the Kandari sector, in the Alpha Quadrant. The system was located near the L-370 and Rigel systems. (TOS: "The Doomsday Machine"; TNG: "Conspiracy" display graphic)
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")