Carlton House was a mansion in London, best known as the town residence of the King. It faced the south side of Pall Mall, and its gardens abutted St. James's Park in the St James's district of London. The location of the house, now replaced by Carlton House Terrace, was a main reason for the creation of John Nash's ceremonial route from St James's to Regent's Park via Regent Street, Portland Place and Park Square: Lower Regent Street and Waterloo Place were originally laid out to form the approach to its front entrance (illustration, right).