A linear luminaire includes a channel with a bottom and sidewalls that arise from opposite sides of the bottom. A printed circuit board (PCB) including a number of LED light engines is mounted in the channel, and may be mounted on stand-offs away from the bottom of the channel. A mounting bracket is connected to an underside of the channel bottom. The linear luminaire also includes a base that can serve as a raceway for wires and cable. The base also has a bottom and sidewalls, and attaches releasably to the channel by means of cooperating engaging structures on the mounting bracket of the channel and portions of the sidewalls of the base.