Mackenzie King Station is a major station on the OC Transpo transitway. It is served by all three of OC Transpo's principal routes along with all express routes and several crosstown routes. It consists of reserved bus lanes on the Mackenzie King Bridge over the Rideau Canal, with indoor waiting areas attached to the adjacent Rideau Centre for westbound buses and the National Defence building for eastbound ones; the two sides are linked by crosswalks and pedestrian underpasses. It is one of the busiest stations, due to the high density, key connections and presence of numerous trip generators.