Washington Square marks the culmination of James's apprentice period as a novelist. With sharply focused attention upon just four principal characters, James provides an acute analysis of middle-class manners and behaviour in the New York of the 1870's, a period of great change in the life of the city. This change is explored through the device of setting the novel's action during the 1840s, similarly a period of considerable turbulence as the United States experienced the onset of rapid commercial and industrial expansion.

Through the relationships between Austin Sloper, a celebrated physician, and his sister Lavinia Penniman, his daughter Catherine, and Catherine's suitor, Morris Townsend, James observes the contemporary scene as a site of competing styles and performances where authentic expression cannot be articulated or is subject to suppression.