1833 – 1923
John A. McMahon has been called “the greatest lawyer in Dayton’s history.” He served in the U. S. Congress from1874 until 1881. During that time, he was chosen by his peers to conduct the prosecution in the first impeachment proceeding brought against a sitting Cabinet member, Secretary of War William W. Belknap. After the cataclysmic 1913 Flood in Dayton, McMahon was called upon to draft the Conservancy Act of Ohio, America’s first regional flood control legislation and the forerunner of the Tennessee Valley Authority, as well as much of the law of regional governance which followed.
McMahon responded to the constitutional challenges provoked by his innovative legislation, culminating in an appearance before the Ohio Supreme Court at the age of 81. He was founder and later president of the Ohio State Bar Association. In a career spanning over 60 years, McMahon was a strong advocate for improvement of the legal and judiciary system through education and through measures enhancing public confidence in the bar.