When Mumford & Sons come to TD Garden on Tuesday, they arrive not just with the distinction of playing a sold-out show. They’ve accomplished something far grander.

“Mumford & Sons went on sale at 10 a.m. and sold out in six minutes,” says Tricia McCorkle, the arena’s director of public relations. “I don’t think we’ve ever had a folk act sell out the TD Garden, unless you consider James Taylor and Carole King a folk act. Pretty incredible.”