Synchronous Fireflies 2027 at Elkmont: Dates, Lottery and Viewing Rules

The synchronous fireflies at Elkmont in Great Smoky Mountains National Park put on their display for about two to three weeks between mid-May and mid-June, and the only way to drive in for the park's viewing event is a vehicle reservation won in a Recreation.gov lottery. The 2027 dates have not been announced. In 2026 the park announced the event on April 21, ran the lottery April 24 to 27, and held viewing nights May 20 to 27, so expect the 2027 announcement in spring with a lottery window of only a few days.

Quick answer: synchronous fireflies 2027

• What: Photinus carolinus, a firefly species whose males flash in synchronized bursts at Elkmont.
• When: peak display lasts about two to three weeks; since 1993 peaks have fallen between mid-May and mid-June. The park predicts the dates from soil temperatures.
• 2027 dates: not announced as of September 27, 2026. Watch the park's news releases and the Recreation.gov lottery page from early spring.
• Lottery cost (2026): $1 to apply, plus a $29 reservation fee if you win.
• Capacity (2026): 120 vehicle reservations per night, 960 for the eight-night event, each good for one passenger vehicle with up to seven people.

What are synchronous fireflies?

Most fireflies flash on their own schedule. Photinus carolinus males flash together. The park describes the pattern as five to eight distinct flashes, followed by about eight seconds of darkness, then the cycle repeats. Across a hillside of thousands of insects, that looks like waves of light switching on and off in the dark woods. The light comes from a chemical reaction in the firefly's abdomen that turns almost all of its energy into light.

Females stay low, on the forest floor and in low plants, which is why the park is strict about staying on the trail. The display is weather-sensitive: heavy rain usually stops the flashing, mist usually does not, and temperatures below 50°F can cut the number of active fireflies.

When do the synchronous fireflies happen?

There is no fixed date. The park uses soil temperatures to predict the best window each year, which is why the dates move:

• 2025: viewing May 29 to June 5, with the lottery May 2 to 5.
• 2026: viewing May 20 to 27, with the lottery April 24 to 27.

So the whole cycle — announcement, lottery, results, viewing — happens within about five weeks each spring. If you are planning a late-May or early-June trip in 2027, book lodging with that in mind, but do not count on winning a reservation.

How the Elkmont firefly lottery works

Based on the 2026 rules from the park and Recreation.gov:

1. Enter on Recreation.gov during the lottery window. In 2026 it opened at 10 a.m. EDT on April 24 and closed at 11:59 p.m. EDT on April 27.
2. Pay the $1 application fee and pick two preferred viewing dates.
3. Wait for the random drawing. In 2026 applicants were emailed by May 6.
4. If you win, a $29 reservation fee is charged to the card you applied with.

Important fine print from the 2025 and 2026 rules: one application per household per season, and reservations are non-refundable, non-transferable and good only for the date issued. After the lottery closes, there are no refunds, changes or cancellations.

Parking and shuttle rules on viewing nights

The current event is a drive-in reservation, not a shuttle ride. The park's 2025 and 2026 announcements describe vehicle reservations only, with no shuttle from outside the area. On viewing nights:

• Access: after noon, Elkmont is open only to vehicles with a reservation and registered Elkmont Campground campers.
• Vehicles: passenger vehicles only, with a maximum of seven people.
• Check-in: 6 p.m. to 8 p.m. No entry after 8:15 p.m., and if you leave you cannot come back in.
• Parking: attendants direct you to the Jakes Creek Trailhead lot, the Appalachian Clubhouse lot or the exit roadway. Little River Trailhead parking is not used for the event, and overnight parking at these lots is not allowed during the event.
• Not allowed: pets on the Jakes Creek and Little River trails, and alcohol anywhere in the viewing area.
• Parking tags: for parking anywhere else in the park during your trip, see Great Smoky Mountains parking tags.

Because a reservation covers one vehicle with up to seven people, a larger group needs more than one winning entry. If your group is 14, plan on at least two cars and two separate households applying.

Viewing etiquette

• Cover your flashlight with red cellophane or use a red-light flashlight, and turn it off once you reach your viewing spot.
• No white light: no headlights, phone screens or flash photography aimed at the woods. Turn off your vehicle's interior and exterior lights.
• Stay on designated trails the whole time. Wandering off-trail crushes the females on the ground.
• Do not catch fireflies.
• Give your eyes a few minutes to adjust to the dark before you judge the show.

What if you don't win the lottery?

• Don't drive in anyway. On event nights Elkmont is closed after noon to anyone without a reservation or a campground registration.
• Try again next year. The lottery is random, and the park runs it every spring.
• Congaree National Park, South Carolina: a different synchronous species, Photuris frontalis, with its own Recreation.gov lottery. In 2026 its event ran May 13 to 20, with the lottery April 7 to 14.
• Other Photinus carolinus sites: the nonprofit Firefly Conservation & Research lists Allegheny National Forest in Pennsylvania and Rocky Fork State Park in Unicoi County, Tennessee, which offers guided viewings.
• See the park by day instead. Our Sugarlands Visitor Center guide covers the park's main Tennessee-side visitor center and the short walk to Cataract Falls.
• Grotto Falls. A popular daytime waterfall hike above Gatlinburg; see our Grotto Falls trail guide for trailhead and parking detail.

Late May and early June are also a good time for the rest of the Smokies. Our Cades Cove guide and things to do in Pigeon Forge cover the other days of a spring trip.

Where to stay for firefly season

Tula & Oak House is in Sevierville, near Pigeon Forge, about 22 minutes from Great Smoky Mountains National Park by the owner's estimate. It sleeps 14 in 5 bedrooms and 5 bathrooms, with parking for up to 5 vehicles — useful when your group needs two cars for two firefly reservations. On the nights you are not at Elkmont, there is a private indoor heated pool, a hot tub, a theater room and a full kitchen. Check your dates and book direct.