Solomon Hillen Jr. (July 10, 1810 – June 26, 1873) was a U.S. Representative from Maryland and mayor of Baltimore.
Hillen was born on the family estate, "Hillen Road", near Baltimore. He graduated from Georgetown College, studied law, was admitted to the bar, and commenced practice in Baltimore. He served as member of the Maryland House of Delegates from 1834 to 1838.
Hillen was elected as a Democrat to the Twenty-sixth Congress (March 4, 1839 – March 3, 1841). Afterward he resumed the practice of law and served as mayor of Baltimore from 1842 to 1845. He died in New York City, and is interred in Section G Lot 40 of New Cathedral Cemetery of Baltimore.