A modular LED line light, the modular LED line light comprising: at least one line light module, the at least one line light module comprising: a U-shaped body comprising a base and two opposing side walls extending from the base, the base comprising an interior surface and an exterior surface; at least one LED array disposed on the interior surface of the U-shaped body; a rail for receiving the at least one line light module, the rail comprising a first surface and a second surface, wherein the first surface is configured to receive the exterior surface of the base of the U-shaped body of the at least one light module; and a cooling tube for receiving a cooling fluid for removing heat from the at least one line light module, the cooling tube being disposed between the exterior surface of the base of the U-shaped body and the first surface of the rail.