U.S. District Senior Judge William J. Nealon of the Middle District of Pennsylvania has died at the age of 95, just days after becoming the longest-sitting U.S. district court judge in history.

Nealon died Thursday morning, according to a statement from Middle District Chief Judge Christopher Conner. Nealon has served on that court for more than 55 years, since December 1962, when he was appointed by President John F. Kennedy.