The Steadman-Nicholson House, located at 414 East Main Street in Union, South Carolina, is a historic residence constructed around 1850. It is a contributing property within the East Main Street–Douglass Heights Historic District, which was added to the National Register of Historic Places in 1989.

The house is a two-story weatherboard residence with Neoclassical Revival influences, featuring:

• A two-story off-centered porch with fluted Ionic columns and a turned balustrade
• A two-story rectangular pedimented bay
• A double-door entrance with sidelights and a semi-circular fanlight

Historic outbuildings include a weatherboard garage with a bellcast roof and a weatherboard barn with a cross-gabled belfry, which has been converted into apartments.

The residence was built for James B. Steadman, a lawyer who later served as a Confederate officer and as Mayor of Union from 1883 until his death in 1885. In 1893, the house was extensively remodeled by William A. Nicholson, a local banker and industrialist who served as president of banks in Union, Buffalo, and Jonesville. Nicholson was also the founder of the Union Oil Mill (1889) and Excelsior Mill (1897).

As a private residence, the Steadman-Nicholson House is not open to the public. However, its architectural features can be appreciated from the street. Visitors are encouraged to view the exterior respectfully from public sidewalks or roads.