Richard Henry Dana Jr. was an American lawyer and politician from Massachusetts, a descendant of a colonial family, who gained renown as the author of the classic American memoir Two Years Before the Mast and as an attorney who successfully represented the U.S. government before the U.S. Supreme Court during the Civil War in the Prize Cases. Both as a writer and as a lawyer, he was a champion of the downtrodden, from seamen to fugitive slaves and freedmen.

Two Years Before the Mast is a memoir by the American author Richard Henry Dana Jr., published in 1840, having been written after a two-year sea voyage from Boston to California on a merchant ship starting in 1834. A film adaptation under the same name was released in 1946.