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The awesome Synchronous Fireflies of Congaree National Park

| Updated Jun 16, 2023

It's an amazing sight that happens every May around this time: a mystery of nature known as the synchronous fireflies display. It happens in the Congaree National Park in South Carolina.

Each year the fireflies somehow are able to coordinate their blinking to turn on and their lights at precisely the same time. Thousands upon thousands of synchronous fireflies doing their thing in unison. It's unlike anything you've ever seen before.

Alas, you won't see it this year because the annual festival devoted to the synchronous fireflies display has been canceled –  another casualty and event cancellation because of the COVID-19 pandemic.

No Synchronous Fireflies Festival this year!

The National Park Service canceled the Synchronous Fireflies Festival, worried that the massive crowds that show up for the event would not be socially distant enough. 

But put the synchronous fireflies on your bucket list for next year.

You really will want to visit this national park and if you can time that visit for this time of the year when the synchronous fireflies display is happening, you'll be very happy campers.

The synchronous fireflies display lasts about a month

Every year for approximately two weeks between mid-May and mid-June visitors to the synchronous fireflies festival at Congaree National Park can experience an awe-inspiring display of synchronous flashing while the fireflies search for a mate. Congaree National park is one of a handful of locations in North America where one can experience the phenomenon of synchronous fireflies.

You can see the synchronous fireflies at Congaree National Park
You can see the synchronous fireflies at Congaree National Park

The park is closed as we write this in mid-May 2020 because of the COVID-19 emergency. When it opens, the annual synchronous fireflies display will most likely have peaked. But this little known national park is still worth a visit, as our RV Podcast off the beaten oath reporters Tom and Patti Burkett, there is still plenty to see. 

But there's one thing they caution no matter for any warm weather visit: Beware of the bugs. Mosquitos to be precise.

Here's their report.

By Tom & Patti Burkett

We were standing on the porch of a national park visitor center, staring at a sign hung above the entrance door.  

It was a half-circle dial with an arrow.  

On the left, at what would be the lowest in its range, it read ‘all clear.’  

At the midpoint was the word ‘severe,’ and at the top of the scale ‘war zone.’  

In big letters across the bottom were the words MOSQUITO METER.  

Ranger Eric, watching us chuckle at the meters, said, “It’s no joke.  Lots of folks call us up and ask what the meter says before they come out here.”  

The meter can be found in Congaree National Park, one of the lesser-known sites in the park system.

A boardwalk lets you go deep into synchronous fireflies territory at the park
A boardwalk lets you go deep into synchronous fireflies territory at the park

Located about fifteen miles southeast of Columbia, South Carolina, it sits at the heart of an international biosphere reserve of the same name.  The entire park is designated wilderness, more than 25,000 acres of it, and many square miles of surrounding countryside contribute to the complete reserve.  

Two newspaper editors, both of whom were sportsmen, began to promote the idea of protecting the area in the early 1960s.  By 1976 it was a national monument, and was designated a national park in 2003.

When it became a park, it had been a biosphere reserve for more than twenty years.  Both the Congaree River and Cedar Creek run through this lush (and mosquito-infested) bottomland forest.  

It is the largest tract of virgin bottomland forest left in the USA and has the largest tract of uncut deciduous temperate forest in the world.  The largest known examples of fifteen tree species can be found on its acres, including a persimmon that tops out over 200 feet, and many oaks that rise more than 130 feet above the wet forest floor.

The awesome Synchronous Fireflies of Congaree National Park 1As you might expect, both the tree cover and the insect food supply make it a haven for birds, and it is internationally known for both variety and population.  

There are more than 25 miles of hiking trails, almost entirely flat, more than two miles of boardwalks, and an excellent canoe trail along Cedar Creek.  The entire park is open to canoeing and kayaking, subject to seasonal flooding and other safety concerns.

Unless you’ve been in a forest like this, it’s hard to convey what it’s like.  The trees tower overhead, their leaves many dozens of feet above your head.  

Very little vegetation grows at ground level, so there’s a vast sense of spaciousness interrupted only by the giant trunks rising intO the distance above you.  Birds sing, insects hum, and something is always falling from up there somewhere—acorns, leaves, twigs, you name it.  

In the water or on the wet ground you can see snakes, turtles, lizards, frogs, and little fish.  You might easily imagine yourself transported back a thousand years to the time when only Native Americans hunted here.

The synchronous fireflies are a great treat for visitors!

One of the great treats of visiting here can be seen in May when they have synchronous fireflies at Congaree National Park

Again, this year (May 2020), the Synchronous Fireflies Festival at Congaree National Park has been canceled for 2020  The Synchronous Fireflies Festival at Congaree National Park had been scheduled for May 11-24 in 2020.

“It was only after careful consideration and out of concern for the health and safety of our visitors, employees, volunteers, and partners, that we made this difficult decision,” Superintendent K. Lynn Berry said.

“The park team enjoys introducing visitors to this awesome natural phenomenon and we know that people love the synchronous fireflies, but safety is our number one priority. There are still uncertainties about where South Carolina will be along the ‘curve’ in mid-May, but there is a need for continued vigilance.”  

Congaree Nationsl Park home of the synchronous fireflies display each May and June
Congaree National Park home of the synchronous fireflies display each May and June

Last year the park welcomed more than 12,000 visitors to the Synchronous Fireflies Festival, a number which would make adhering to social distancing guidelines impossible this year. The park also lost valuable planning time in March and April, which are the key preparation months. The ability to recruit and train more than 100 volunteers, collaborate with partners, and bring in additional staffing resources has been severely limited.  

Battle for a spot in the lottery at the Great Smoky Mountains if you like, or visit Congaree National Park for a much less crowded experience.  You can walk the boardwalk through the firefly area, at your leisure.  

The limited parking does tend to fill up, though, so we’d suggest you come early, take a nap. check out the visitor center, and be in a prime spot when glow time begins.  

It’s nature’s world out here, so don’t forget the insect repellent, but don’t miss the chance to stroll through the forest primeval, out here off the beaten path.

And don't forget to try and visit in mid-May or early June so you can see the synchronous fireflies.


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Mike Wendland

Published on 2020-05-16

Mike Wendland is a multiple Emmy-award-winning Journalist, Podcaster, YouTuber, and Blogger, who has traveled with his wife, Jennifer, all over North America in an RV, sharing adventures and reviewing RV, Camping, Outdoor, Travel and Tech Gear for the past 12 years. They are leading industry experts in RV living and have written 18 travel books.

4 Responses to “The awesome Synchronous Fireflies of Congaree National Park”

June 02, 2020at5:35 pm, Leslie said:

We love nearby and have seen the Firefly Festival grow tremendously. Of note last year the boardwalk was reserved for handicap access only. There is a path set up for you to view the fireflies from at ground level. We enjoy walking the loop several times as you can see the full effect of the fireflies. Also only use red light so to not interrupt the fireflies also keep voices low.

May 18, 2020at8:31 am, 8 Best Bike Trails In The U.S. | RV Lifestyle said:

[…] listening to one of our recent podcasts for the RV […]

May 17, 2020at8:01 am, Bev Parkison said:

We visited in early November 2018 and there were no mosquitos. Paddling the creek through the giant cypress trees was an unforgettable experience. The boardwalk areas are stunning. I highly recommend a visit to this wonderful national park.

May 16, 2020at10:10 pm, Paul said:

If you’d like to learn more about fireflies, Lynn Frierson Faust was recently a guest on Creature Comforts (a production of MPB Think Radio). You can listen to the podcast at

Ms. Faust authored “Fireflies, Glow-Worms, and Lightning Bugs: Identification and Natural History of the Fireflies of the Eastern and Central United States and Canada”:

Want to learn more?

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