Lindley Hoag Hadley (June 19, 1861 – November 1, 1948) was a U.S. Representative from Washington.

Born near Sylvania, Indiana, Hadley attended the common schools of his native city, Bloomingdale (Indiana) Academy, and Illinois Wesleyan University, Bloomington, Illinois.

He moved to the State of Washington in 1890 and settled in Whatcom (now Bellingham), where he practiced law until elected to Congress.

Reengaged in the practice of law in Washington, D.C., until 1940, when he retired from active life and moved to Wilton, Connecticut.

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