Around 1850, William Bonner built two farmhouses on the site. William's family lived in the west house while his older brother, James, and his family lived in the east house. Prior to the homes being built, the families resided in the township of Bristol, Wisconsin. By 1861, James had purchased his own farm off Route 45.
The most historically significant structure on the property is the main barn. The original oak-and-hickory structure was built in 1848. Measuring 40 by 44 feet, it held just five cows. This portion of the main barn is among the oldest surviving intact great barns in Lake County.
As the family prospered over the century, the barn reflected that with the addition of four expansions and two silos. The first was a white pine sawn timber bay added to the north end around 1890. The second was added to the north of the first addition. The third barn addition was probably constructed in the mid-1920s. It is a combination timber frame with gambrel trusses and was used for dairying on the ground level and hay storage on the upper level. The final addition became the milk house and was constructed on the west side of the barn. Two concrete stave silos were constructed on the north end of the main barn. They are a representative architectural feature of any dairy farm.
A two-story granary barn sits on the western edge of the property and measures 24 by 40 feet. It was probably built around 1943. It is a fine example of the type of granaries built on farms in the first half of the century.
In addition, a 1920s gambrel roof hay barn occupies part of the site. It was constructed at the end of the great barn building period. It includes some timber from older buildings, but the primary timber is yellow pine, probably shipped from the west coast. By this period, most of the great Midwest pineries had already been logged off.
Also around 1850, William Bonner erected a building as his carpenter's shop. In addition to the farmhouse and original portion of the main barn, this is the only other existing structure built by William Bonner. A portion of the building, once used as a granary, has old blacksmith forged iron hinges and handmade nails reaffirming this as one of the oldest buildings on the site.
The farm also includes a pump house, chicken coop, hog house, and storage shed. The smallest structure on the property is a 19th-century outhouse.