The 7900 square feet Georgian floor plan includes a stunning curved staircase, large foyers on both floors, a music room, parlor, library, dining room, kitchen, 7 bedrooms, multiple bathrooms, and a third story cupola. A brick wing behind the main house once was used as servant's kitchen, well, laundry house, quarters and a smoke house. The carriage barn, located behind the brick wing, still houses the Duncan's carriage; plans for restoration are underway. Unique architectural aspects of this mansion include frescoed ceilings in the music room and dining room, mosaic tiles and turn of the century stenciling and faux graining in the main foyer and beautiful chandeliers.

T.C. and Fannie Duncan had 2 sons (both died at a very young age) and 3 daughters: Medora Eleanor Duncan Fitten (1887-1960), Louisa Merriman Duncan Eaves (1890-1975), Fannie Merriman Duncan (1897-1974). Medora married and moved to Atlanta; Louisa and Fannie lived at Merridun until their deaths. Louisa's only son, Thomas Cary Duncan Eaves and his wife Juliet Caruana Eaves, inherited Merridun; seven generations of the Benjamin Rice family enjoyed the pleasures of Merridun prior to being sold in the summer of 1990. Portraits of Thomas Cary Duncan and his wife, Fannie Merriman Duncan hang in the foyer and parlors.