A visiting judge is a judge appointed to hear a case as a member of a court to which he or she does not ordinarily belong. In United States federal courts, this is referred to as an assignment "by designation" of the Chief Justice of the United States (for inter-circuit assignments) or the Circuit Chief Judge (for intra-circuit assignments), and is authorized by 28 U.S.C.§ 292.
Kopf, Richard George (July 28, 2013). "Have Robe, Will Travel". Hercules and the Umpire: The Role of the Federal Trial Judge. Retrieved July 28, 2013. "A United States federal district judge's anecdotal description of the designation process: Let’s say you are prosecuting or defending a criminal or civil case in your local federal district court, and, out of the blue, your case get reassigned. Not only do you have new judge, but the new judge is a senior status district judge from far away.... How does that happen? Here’s a primer."