As its name suggests, the German Club/Assay Office has witnessed a remarkable series of events during its history. In 1868, Thomas Prosch, noted newspaper publisher, civic leader and secretary of the Chamber of Commerce in Seattle, built the two-story, Italianate building, for offices and an entertainment hall. In 1898, the Federal government decided it needed an assay office in Seattle to weigh and evaluate the massive amounts of gold flowing into the city from the Yukon. It rented the simple brick building and used its rooms for office and storage spaces. Returning Klondike miners, anxious to secure the best price for their gold, formed lines in front of the Assay Office that stretched back for blocks. Government officials weighed, melted and molded once-raw gold into bars, stamped the bars with Federal seals and sent them east to the mint in Philadelphia. The miners received certified government checks in exchange for the gold deposits that averaged over 20 million dollars during the early years.

The Assay Office remained open for years, but slowing gold deposits led to its closure in 1935. During the brief period before World War II, Deutsches Haus purchased the building and used it as a gathering place for German-Americans, but during the war Seattle women's organizations took over and renovated the building. Groups like the Colonial Dames and the English Speaking Union turned the second floor into a ballroom and hosted dances for U.S. military officers. After the war, the use of the building was returned to its German-American owners. Today the German Club is only open to member organizations, occasional renters, German language classes and meetings with politicians.

The German Club is located at 609 Ninth Ave., east of I-5. The building is not open to the public.