The McIlwain House, also known as the Foster Jordan House, is a historic residence located at 418 East Main Street in Union, South Carolina. Constructed circa 1823 by a local brick mason named McIlwain, the house is one of the earliest surviving brick homes in Union County. 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 has been associated with the Jordan family for much of its history. City directories indicate that A. Foster Jordan resided there in 1954, followed by Elizabeth Jordan in 1984, and Marsha E. Jordan in 2014.

As a private residence, the McIlwain House is not open to the public. Visitors are encouraged to view it respectfully from public sidewalks or roads.