Synchronous Fireflies at Congaree

Synchronous Fireflies light up the forest at dusk. (NPS Photo)

Updated: March 30, 2025

Synchronous Fireflies Viewing Event

With over 2,000 species found world-wide, there are only three species of synchronous fireflies that can be found in North America. Every year, Congaree National Park hosts synchronous fireflies for approximately two weeks between mid-May and mid-June. During this time visitors can experience an awe-inspiring display of synchronous flashing while the fireflies search for a mate. This special and unique phenomenon is extremely popular. Below you will find information about this year's event, the lottery, park access during the synchronization period, and important guidelines for those coming to see these flashy fliers light up the night.

Firefly Viewing Event Dates & Information

This year’s event will take place May 14-21 and feature some slight modifications compared to past years with the continuing goal of providing the best viewing experience possible for visitors and ensuring the long-term sustainability of this signature annual event. These updates are based on continued improvements in the park’s ability to forecast when synchronization will reach peak and observations and feedback from visitors attending past events. Modifications include:

• Scheduled event dates occur during the period of peak firefly synchronization, so that visitors can experience this phenomenal natural display at its best.
• A decrease in the event fee by $5 by providing low lumen red flashlights for pass holders to borrow and return at the end of the evening.

Firefly Viewing Event Lottery Information

Passes will be required to enter the park on event nights and will be awarded through a lottery system hosted through Recreation.gov.

This year’s pass lottery will begin at 10:00 a.m. EDT Thursday, April 3 and will remain open for one week, ending at 10:00 a.m. EDT Wednesday, April 9. Entries must be made through the online lottery page at https://www.recreation.gov/ticket/facility/300008 and are limited to one per household. All lottery applicants will be charged a $1 non-refundable service fee upon entering the lottery. Applicants who are awarded passes will be charged the remaining $19 event fee to secure their pass, for a total cost of $20. A total of 145 passes will be available for each event night. All applicants will be notified on Wednesday, April 16 whether they have or have not been awarded a pass.
Passes will admit one passenger vehicle with up to 2 axles that can fit in a standard parking space. During the event, vehicles such as RVs, vehicles with trailers, large passenger vans, buses or mini-buses, will not be admitted. Vehicles may have a maximum of 8 passengers. Passes may only be used one time, are only valid for the date listed. Passes are non-transferable. Gates on event nights will open for those with valid event passes beginning at 7:00 p.m. and close to entry at 8:30 p.m.

PLEASE NOTE: All questions or technical assistance requests concerning the lottery should be directed to Recreation.gov (877-444-6777), as the park does not manage the lottery system.

Park Closures During Firefly Synchronization

To best protect critical firefly habitat and allow park staff and volunteers to prepare for the event, certain areas of the park will be closed to all visitors at 4:30 p.m. daily. During this period the following areas will be closed:

• The Harry Hampton Visitor Center, boardwalk, and frontcountry hiking trails.
• Bannister Bridge Canoe Launch.
• Cedar Creek between Bannister Bridge and South Cedar Creek Canoe Launch.
• Longleaf and Bluff Campgrounds

Additionally, no backcountry camping permits will be issued during the period of the viewing event.

Basic Fireflies Event Etiquette and Information

Because these fireflies need specific habitat and conditions in order to synchronize, Congaree is one of only a few places where these conditions are present, and that visitors can experience this natural wonder. In order to provide you and fellow visitors with the best experience and to ensure there are fireflies for the future, please remember the following:

• Keep flashlight use to a minimum, and only use lights that have a red-mode or have a red filter.
• Keep all flashlights, when in use, pointed at the ground.
• Cell phones may not be used in the viewing area for either a light source or taking photos/video.
• No pets are permitted in the park during this event. Service animals are welcome.
• All visitors should stay on the designated Firefly Trail.
• Catching or disturbing fireflies is not permitted at Congaree National Park.
• No insect repellent can be applied after arrival at the park. Please apply prior to arrival.
• Viewing the fireflies is best just after dark, usually between 9:00 p.m. and 10:00 p.m.
• Thunderstorms often occur during this time, so be prepared for the weather. Rain can slow down or stop firefly activity for the evening.