Henry St. John (July 16, 1783 – May 17, 1869) was a U.S. Representative from Ohio.

Born in Washington County, Vermont, St. John received limited schooling. He served during the War of 1812 before moving to Wooster, Ohio, in 1815. Later, he moved to Crawford County, Ohio. In 1837, he settled in Seneca County, where he engaged in agricultural pursuits, milling, and storekeeping near Tiffin, Ohio.

St. John was elected as a Democrat to the Twenty-eighth and Twenty-ninth Congresses (March 4, 1843 – March 3, 1847). He was not a candidate for renomination. After leaving Congress, he resumed agricultural pursuits. Resided in Tiffin, Ohio, where he died in May 1869.

• United States Congress. "Henry St. John (id: S000767)". Biographical Directory of the United States Congress.

 This article incorporates public domain material from the Biographical Directory of the United States Congress