Address: 24206 SE 216th Street, Maple Valley. The Olof and Mathilda Olson House sits on a plateau above the Cedar River about a mile east of Maple Valley. The Olsons purchased their 80-acre parcel in 1898. Olof worked as a contractor for the Northern Pacific and Great Northern Railroads, and specialized in tunnel construction. His work certainly influenced their decision to build a poured concrete house rather than a wood frame house. The large two-story square house with a hip roof and broad eaves suggests the influence of the Prairie style.
The barn, built in 1909, is noteworthy as one of the few historic barns in King County with barrel-vault construction. In the early 1990s, the pastures surrounding the house were developed as a links-style golf course and the house renovated for use as the course club house and reception facility.