Bob Lemmon House is a historic farmhouse located near Winnsboro, Fairfield County, South Carolina. It was built about 1850, and is a two-story, frame I-house. It has a gable roof, a single pile, central hall plan, and rear shed room additions. The façade features a two-tiered pedimented portico with four wooden Tuscan order columns. The property also includes a shed (c. 1910) and a barn (c. 1890), both of frame construction sheathed in weatherboard. It was added to the National Register of Historic Places in 1984.