The Key Route Inn was a major hotel in Oakland, California in the early decades of the 20th century. It was constructed by the Realty Syndicate of Francis "Borax" Smith and Frank C. Havens, a subsidiary of which was the Key Route transit system. The Inn first opened on May 7, 1907 straddling what is now Grand Avenue along the west side of Broadway. President William Howard Taft and his party were guests in 1909. Key Route Inn was a massive wood-framed structure with open timbering, in imitation of an old English style. One of its most remarkable features was the large archway and corridor through which the tracks of one of the Key Route's transbay lines passed. In this corridor was a stop which connected to the main lobby of the hotel.
The Key Route Inn suffered major damage from a fire which occurred on September 8, 1930, and combined with the Great Depression just getting underway, as well as the desire of the City of Oakland to connect Grand Avenue with 22nd Street, resulted in the Inn being fully demolished in April and May, 1932, 25 years after it had first opened.
The rail line, however, continued, becoming the "B" transbay line upon the opening of the San Francisco – Oakland Bay Bridge railway. The rail line was replaced by the "B" bus route in April 1958, and was subsequently incorporated into the publicly-owned AC Transit system.