James Henthorn (1744 – 28 December 1832)^[2] was the president of the Royal College of Surgeons in Ireland (RCSI) in 1822.^[3]

James Henthorn was appointed Surgeon to the House of Industry Hospitals, on December 7. He was a member of the Dublin Society of Surgeons, and his name is in the first charter granted to the RCSI in 1784. Sir Charles Cameron states: "there is every reason to believe that the real founders of the college were the elder Dease and Henthorn."^[2] Henthorn was Surgeon at the Lock Hospital. When he became a Governor of the House of Industry Hospitals, he played the key role in inducing the Government to erect the Richmond, Hardwicke, and Fever Hospitals.^[4]

Henthorn published papers on the treatment of syphilis in the Dublin Hospital Reports for 1808–9. A full-sized portrait of Henthorn, painted by Martin Cregan, is placed in the college meeting-room. ^{[citation needed]}

• List of presidents of the Royal College of Surgeons in Ireland