The Great Smoky Mountains National Park is gearing up for its annual synchronous fireflies event—the largest gathering of synchronous fireflies in the Western Hemisphere. During the annual phenomenon, swarms of lightning bugs will light up the park at night. The incredible flashing display is so popular that a lottery system has been established for obtaining the coveted parking passes required to attend. Here’s how to get one and what to expect.
How to see the Great Smoky Mountains synchronous fireflies
In 2024, the lottery to see the synchronous fireflies in the Great Smoky Mountains National Park opens on April 26, at 10 a.m. EST, and will close on April 29, 2024, at 11:59 p.m. EST. Those interested in seeing the annual display can enter the lottery at Recreation.gov, and will be charged a $1 lottery application fee.
The 2024 viewing dates for the Great Smoky Mountain synchronous fireflies will be June 3 to June 10. Some time in mid-May, lottery applicants will be notified about whether their application was accepted or rejected.
Lottery winners will automatically obtain (and be charged for) the vehicle pass necessary to access the viewing area. The Great Smoky Mountains National Park will be handing out a total of 1,120 vehicle passes for the eight-day event (140 per day). Lottery winners will be charged $24 per vehicle and can bring a maximum of seven passengers in their car.
Attending the event
Each pass is valid only for a specified date, and an arrival time between 6:00 p.m. and 8:00 p.m. will be assigned. No additional passes beyond those assigned during the lottery will be made available.
Attendees will be asked to cover their flashlights with red or blue cellophane so they don’t disrupt the viewing experience, turn them off altogether when they have found a viewing spot, and stay on designated trails or paved surfaces at all times. And remember: No firefly-catching allowed, so leave those Ball jars at home, folks.
After visitors check in, parking attendants will direct vehicles into designated parking areas, where visitors can then leave their cars during the viewing. A designated number of ADA parking spaces will be available on a first-come, first-served basis. Primary viewing areas are Jakes Creek and Little River trails.
The firefly display takes place in the Elkmont section of the Great Smoky Mountains National Park.
Photo by William Silver/Shutterstock
What are synchronous fireflies?
Synchronous fireflies are a unique species of firefly (which is a type of beetle also known as a lightning bug) that can actually synchronize their flashing light displays. Their light patterns, which are produced in “lanterns” along their abdomens, are part of a mating ritual that helps males and females recognize each other. The males will fly and flash their light and the typically stationary females will respond with a flash, according to the Great Smoky Mountains National Park’s dedicated synchronous fireflies page.
No one is exactly sure why the fireflies flash their lights in unison, and they don’t always do so. When they do, a burst of light ends with an abrupt period of darkness.
Fireflies’ bioluminescent lanterns are tucked into their abdomens.
Photo by Suzanne Tucker/Shutterstock
The peak mating season lasts for approximately two weeks each year, and the dates of the display vary from one year to the next. Scientists predict the dates based on factors such as temperature and the moisture in the soil. Even during the peak season, attendees aren’t guaranteed a perfect display, the park has cautioned. Environmental factors such as rainfall or cooler temperatures that fall below 50 degrees can shut down the display on any given night.
Other places to see synchronous fireflies in the USA
While the Great Smoky Mountains may have one of the most well-known firefly displays, other U.S. parks also welcome synchronous fireflies each year. While the lottery for these parks are now closed, those interested in attending should take note for 2025.
Congaree National Park
This year’s annual synchronous firefly viewing event at Congaree National Park will take place from May 16 to 25, 2024. Similarly to Great Smoky Mountains, visitors need to win parking passes via a lottery system to attend. The lottery opened on April 4 and closed on April 10. Winners were notified on April 16. Parking passes cost $24 per vehicle for this event.
Allegheny National Forest
There are 15 species of firefly in Pennsylvania, and June is prime time to see them. The PA Firefly Festival takes place annually in Tionesta and is scheduled for Friday, June 28, and Saturday, June 29, in 2024. Registration for the 2024 lottery is now closed.
This article originally appeared online in 2019. It was most recently updated on April 24, 2024, to include current information.
