Every year in late May or early June, thousands of visitors gather near the Elkmont Campground located in the Great Smoky Mountains National Park, to witness the naturally occurring phenomenon of “Photinus carolinas,” a firefly species known for flashing synchronously. There are 19 species of fireflies that live in Great Smoky Mountains National Park, but Photinus carolinas is the only species in America whose individuals can synchronize their flashing light patterns.

Fireflies (also called lightning bugs) are beetles. Their light patterns are part of their mating display. Each species of firefly has a characteristic flash pattern that helps its male and female individuals recognize each other. Most species produce a greenish-yellow light. The males fly and flash and the usually stationary females respond with a flash.
It is not understood why the fireflies flash synchronously. The fireflies do not always flash in unison, and instead flash in waves across hillsides, and at other times will flash randomly. Synchrony occurs in short bursts that end with abrupt periods of darkness.

The firefly shuttle operating dates are June 2-9, 2015. Advance reservations of parking passes have sold out, however, 85 parking passes will be available for each day of the event. These 85 passes will go on sale online at 10:00 a.m. the day before the event. Passes can be purchased online at www.recreation.gov or by calling (877) 444-6777. During the program operating dates, a parking pass is required for evening access tp the Sugarlands Visitor Center parking lot and the firefly shuttle to the Elkmont viewing Area.

Elkmont is not the only place to view synchronous fireflies. On many occasions, synchronous fireflies have made an appearance at Up the Creek RV Camp in Pigeon Forge, TN.