On the site of Isaac’s boyhood home, Anton Billmeyer built Shadowlawn for Isaac Witter in 1907. The house was built on grounds consisting of 230 feet of frontage on Third Street and 230 feet of frontage on the Wisconsin River.
The house was built in the neoclassical style and consists of 23 rooms, not including the large halls and had a central vacuum system. An elevator was installed after Isaac became ill.
In 1947, Isaac’s brother-in-law, George W. Mead, purchased the Witter home and grounds for $15,000.00 and presented it to the city to house the T.B. Scott Public Library, which opened in 1948.
After the McMillan Memorial Library was built and opened in 1970, the building and land were deeded to the South Wood County Historical Corporation for the museum, which opened in 1972.