Fireflies of Rocky Fork State Park among region’s most popular glow shows

Synchronous fireflies work their mating magic over Rocky Fork Creek at Triple Falls about 100 yards up Rocky Fork Trail in Flag Pond, Tennessee. (Photo courtesy of Cory Franklin) Click here to view more images contributed by Appalachian Places staff and Park Ranger Cory Franklin.

By Mark Rutledge 

It’s late spring and a few groups of lucky lottery winners are about to gather for some deep-woods wonderment at Lamar Alexander Rocky Fork State Park in Flag Pond, Tennessee. For those who won the free online lottery, the show is about to begin. For everyone else, well, better luck next year. 

Park Ranger Cory Franklin briefs a group on protocols and what to look for (Click the photo to view a short video.) before a night of synchronous firefly viewing in June 2025 at Rocky Fork State Park in Flag Pond, Tennessee. (Photo by Appalachian Places staff)

It is the rare spectacle of fireflies — both blue ghost and synchronous species — that turns Rocky Fork State Park into a magical, flashing landscape just before the start of summer. Typically held in late May and early June, the viewing events offer a limited number of visitors the chance to witness thousands of fireflies blinking in perfect unison, a dazzling mating display unique to just a few spots in the world.  

Participants set up to view synchronous fireflies along Rocky Fork Trail. (Photo by Appalachian Places staff)

In Southeast Asia, synchronous fireflies are more common. In North America they’re not as easy to find, but the Appalachian mountains offer some hospitable environments and excellent viewing opportunities. The Great Smoky Mountains National Park has one of the best-known viewing locations in the park’s Elkmont, Tennessee, region. Also lottery-based due to high demand, participants receive a vehicle reservation for a specific night during the viewing periods in late May and early June.

Viewing participants are required to use red flashlights and turn smartphone displays to red to avoid disturbing the fireflies. (Photo by Appalachian Places staff)

The lottery at Rocky Fork State Park is announced during April on the park’s Facebook page. Winners pay a $50 fee per vehicle. Vehicles can carry up to six participants.

Like the Great Smoky Mountains program, Rocky Fork’s viewing opportunities are possible because the park’s stream and forest areas provide a pristine habitat for synchronous fireflies, which have the rare ability to synchronize their flash patterns. Instead of random firefly displays that are typical for most any backyard or wooded area, the forest floor and tree canopy lights up simultaneously with synchronous fireflies, followed by a brief period of total darkness, creating a wave effect.  

The early viewing dates are focused on blue ghost fireflies. Instead of flashing in unison, male blue ghosts will hover near the forest floor. They get their name from maintaining a pale and ghostly glow for up to a minute while searching for the brighter glow of wingless females among the leaf litter below.

For those who want to learn more about fireflies, Park Ranger Cory Franklin recommends this book. (Photo by Appalachian Places staff)

Attending the firefly event at Rocky Fork is a controlled experience designed to protect the fragile habitat of the insects. Because the fireflies are sensitive to light and human disturbance, visitors must follow a few simple protocols. Because white light can disrupt the firefly mating process, visitors are advised to use red-light flashlights to preserve the natural darkness, and to switch smartphones to a red-light screen.

Viewers are directed to a parking area and make their way from there to the Rocky Fork Trail access. Personal folding chairs are advisable for finding suitable viewing areas from the trail. After a brief informational and instructional program, dusk falls and the show begins.

Initially, the flashes might be sporadic, but as nightfall deepens, the bugs begin to blink together in waves of light that wash over the landscape. It’s often described as a quiet, contemplative, and mesmerizing experience.

Mark Rutledge is managing editor of Appalachian Places.