Charles and Mary Routh Dahlgren’s Greek Revival house was originally named Routhland, the same name as the house that preceded it and burned in 1855. It was renamed Dunleith by its second owner, who had no connection to the Routh family. Dahlgren described the construction in an 1886 letter, “I rebuilt the house after a plan by Mr. A. J. Downing, carried out by Mr. Crothers, one of the best and ablest mechanics.” Downing died three years before the fire, but his publications may have influenced the plan and design of the Gothic Revival outbuildings. John Crothers (1819–1906), a native of Maryland, likely designed and built the house. In partnership with Thomas Bowen, Crothers built several houses before moving to St. Louis in the 1860s.
Dunleith’s peripteral giant-order colonnade is the only one to survive in Mississippi. Not only is it architecturally impressive, but it responds to the subtropical climate of Natchez by shading all the building’s walls and allowing floor-length windows and hinged doorway sidelights and transoms to remain open in the rain. Typical of other Natchez mansions, the central hallways are fully open to cooling breezes because the staircase is in a side hall between the library and dining room and it continues unbroken to the attic, which is vented by dormer windows. The house’s roof balustrade was removed for installation of the clay tile roof in the early twentieth century.
Records from the Andrew Brown and Son sawmill document that construction began in October 1855 and was substantially completed by May 1857. As in other Natchez houses built between 1855 and 1860, Dunleith, a National Historic Landmark, combines elements of Greek Revival and the newly popular Italianate style, seen especially in the cornice brackets, flared eaves, and the side consoles on the dormers.
Dunleith retains all its original acreage and original outbuildings. Adjoining the rear gallery is a three-story brick service wing with a hipped roof and a three-story gallery. This wing originally contained the kitchen, laundry, storage rooms, and quarters for enslaved workers. Other outbuildings include a brick poultry house with a hipped roof and three Gothic Revival brick buildings with crenellated parapets, including a greenhouse, a carriage house (now a restaurant), and a dairy.