Herbert and Katherine Jacobs Second House, Madison

The Herbert and Katherine Jacobs Second House, often called Jacobs II or the Solar Hemicycle, is a landmark of mid-century modern design. Constructed between 1946 and 1948 and designed by Frank Lloyd Wright, it represents the second home Wright created for the Jacobs family-this time in a sweeping semicircular form inspired by the sun’s trajectory and earth-sheltering principles.

Unlike the earlier Usonian Jacobs I, the Second House integrates a hemicycle floor‑plan, partially embedded into an earthen berm to create natural insulation and energy efficiency. Wright’s design addresses passive solar heating by orienting the curved facade toward the sun and crafting a double-height living room that expands across a half-circle opening onto the surrounding landscape.

Over its construction, the Jacobses played an active role-partly due to contractor issues and cost considerations, they took on much of the building themselves. Wright ultimately stepped back from the project, and the couple completed key elements of the home under guidance.

Recognized for its architectural innovation, the Jacobs Second House was listed on the National Register of Historic Places in 1974, and designated a National Historic Landmark in 2003. Though privately owned today, the house is celebrated as a rare and beautifully executed realization of Wright’s solar‑centric, earth‑integrated Usonian vision.