Most nineteenth-century commercial structures are usually considered Italianate in style. However, many buildings contain a variety of detailing not associated with Italianate. These commercial buildings have been divided into four categories: the single storefront, generally twenty-five-feet wide with one entrance; the double storefront, with a width of fifty feet or more and two or three entrances; the corner building which may have entrances on two sides and sometimes a diagonal corner entrance; and the commercial block which generally covers a large area with multiple entrances.
Most nineteenth-century commercial buildings are two or three stories in height, with a flat roof and a variety of ornamental detailing. The "textbook" storefront has a recessed central entrance flanked by large display windows with kickplates, window and door transoms. The primary or roofline cornice is often bracketed with parapets, finials, or simple decorative panels. There is sometimes a secondary cornice separating the first two stories, which sometimes repeat the pattern of the upper cornice. Windows on the upper stories are generally smaller than the display windows on the street level and are usually decorated with molded surrounds, radiating voussoirs, or plain stone lintels.
Some of the most ornate nineteenth-century commercial structures feature cast iron façades. These had Italianate features particularly at the cornice. Richardsonian elements are also evident on some of these structures. The key to distinguishing a nineteenth-century building is the predominately glass storefront and smaller windows on the upper stories. These buildings are usually retail, offices, and hotel space.