Herbert and Katherine Jacobs Second House is a historic house located at 3995 Shawn Trail in Madison, Wisconsin, United States. Built in 1946-48, the house was the second of two designed by Frank Lloyd Wright for journalist Herbert Jacobs and his wife Katherine. The house's design is unique among Wright's works; he called the style the "Solar Hemicycle" due to its semicircular layout and use of natural materials to conserve solar energy. The house was added to the National Register of Historic Places in 1974 and declared a National Historic Landmark in 2003.