Silas Zephaniah Landes (born May 15, 1842) was a Democratic member of the United States House of Representatives from Illinois. He represented Illinois’s 16th Congressional District and served as a federal legislator during the 1880s. Landes was elected as a Representative in the U.S. Congress as a member of the Democratic Party.

Landes served two terms in the House of Representatives, holding office from December 7, 1885, to March 3, 1889. During this period, he represented the interests of his Illinois constituents at the national level. Identified in congressional records by the biographical guide ID L000048, he is recognized as a historical member of Congress and is noted specifically for his service as a Representative from Illinois in the 16th District.

After leaving office in 1889, Landes was no longer in public office at the federal level and is regarded as a former member of Congress. His tenure from 1885 to 1889 situates him among the Democratic representatives who served during the late nineteenth century.