12 Washington Square North is part of a row of Greek Revival houses east of Fifth Avenue. All of the houses on this row were apparently built at the same time, between 1832-1833. Handsome porticoes, consisting of fluted Ionic columns carrying a full entablature, grace the entrances of these grand town houses. The doors are framed with sidelights and simple transoms and have paneled pilasters supporting the transom bar. Most of the houses retain entrance doors with a pair of vertical panels enframed by egg and dart moldings. The stoops have stone balusters and paneled newels, except for No. 12 which has paneled, stepped wing walls without balusters. In 1872, the house at Fifth Avenue corner, No. 13, was combined with No. 12 to form a double mansion for William Butler Duncan