The coordinated insects, which put on a light show each year as the males fill the forest with simultaneous blinks at night, have surged in popularity. As interest increased, the National Park Service had to start managing visitation, first restricting access to shuttle service only and then by initiating a first-come-first-serve online reservation system. This year, the park is using a lottery system for the first time. 

The lottery will be held for an eight-day peak period, from Tuesday, May 31, to Tuesday, June 7. A total of 1,800 passes are available. Lottery winners will be charged a $1.50 reservation fee and awarded a parking pass for Sugarlands Visitor Center near Gatlinburg, where they will catch a shuttle to see the fireflies at Elkmont. 

Enter the lottery at www.recreation.gov.