Sydenham Elnathan Ancona (November 20, 1824 – June 20, 1913) was an American educator and politician who served three terms as a Democratic member of the U.S. House of Representatives from Pennsylvania from 1861 to 1867.

[citation needed] Ancona was elected as a Democrat to the Thirty-seventh, Thirty-eighth, and Thirty-ninth Congresses.

He was one of the organizers of the Reading Fire Insurance and Trust Company, serving as its secretary and treasurer for over 30 years.

During a visit to the Capitol at Washington, D.C., in 1912 he was tendered a reception on the floor of the House of Representatives, because he was at the time the last surviving Member of the Thirty-seventh Congress which had been assembled at the extraordinary session called by Abraham Lincoln on July 4, 1861.

This article about a member of the United States House of Representatives from Pennsylvania is a stub.