The trigger electronics for the muon system of the Fermilab D0 detector is described. The hardware trigger consists of VME-based cards designed to find probable tracks in individual chambers and then match these track segments. The fast trigger is highly parallel and able to discern probable tracks from about 15,000 trigger cells in under 200 ns from receipt of all bits in the counting house. There is a parallel confirmation trigger with a response time of 1--5 microseconds that provides a crude calculation of the momentum and charge of the muon. 6 refs., 7 figs
