Some of the longest-serving mayors in the United States are listed according to their length of service in that currently or has served in that part of the state or legislative office.
(If there is a break in their service, then this length is measured from their return to the office.)
The longest-serving current mayor of one of the 50 largest cities in the United States is Jean Stothert, who has been mayor of Omaha since June 10, 2013.
A list of mayors in order of their total length of service.
(If there is a break in their service, then this length is measured as the sum of their terms.)