Every year in late May or early June, thousands of visitors gather near the popular Elkmont Campground to observe the naturally occurring phenomenon of Photinus carolinus, a firefly species that flashes synchronously. Since 2006, access to the Elkmont area has been limited to shuttle service beginning at Sugarlands Visitor Center during the eight days of predicted peak activity in order to reduce traffic congestion and provide a safe viewing experience for visitors that minimizes disturbance to these unique fireflies during the critical two-week mating period.The lottery will be open for applications from Friday, April 28 at 12:00 noon until Monday, May 1 at 8:00 p.m. Results of the lottery will be available on Wednesday, May 10. A total of 1,800 vehicle passes will be available for the event which includes: 1768 regular-parking passes (225 per day) which admit one passenger vehicle up to 19’ in length with a maximum of six occupants, and 32 large-vehicle parking passes (four per day) which admit one large vehicle (RV, mini-bus, etc.) from 19’ to 30’ in length, with a maximum of 24 occupants. Lottery applicants must apply for either a regular-parking pass or large-vehicle parking pass and then may choose two possible dates to attend the event over the eight-day viewing period.The lottery system uses a randomized computer drawing to select applications. There is no fee to enter the lottery this year. If selected, the lottery winner will be charged a $2.75 reservation fee and awarded a parking pass. The parking pass permits visitors to park at Sugarlands Visitor Center and allows occupants to access the shuttle service to Elkmont.Parking passes are non-refundable, non-transferable, and good only for the date issued. There is a limit of one lottery application per household per season. All lottery applicants will be notified by e-mail on May 10 that they were “successful” and awarded a parking pass or “unsuccessful” and not able to secure a parking pass.The number of passes issued each day is based primarily on the Sugarlands Visitor Center parking lot capacity and the ability to accommodate a large number of viewers on site. Arrival times will be assigned in order to relieve traffic congestion in the parking lot and also for boarding the shuttles, which are provided in partnership with the City of Gatlinburg. The shuttle buses will begin picking up visitors from the Sugarlands Visitor Center RV/bus parking area at 7:00 p.m. The cost will be $1.00 round trip per person, as in previous years, and collected when boarding the shuttle. Cash will be the only form of payment accepted.The shuttle service is the only transportation mode for visitor access during this period, except for registered campers staying at the Elkmont Campground. Visitors are not allowed to walk the Elkmont entrance road due to safety concerns.Visitors may visit the website www.recreation.gov and search for “Firefly Event” for more information and to enter the lottery. Parking passes may also be obtained by calling 1-877-444-6777, but park officials encourage the use of the online process. The $2.75 reservation fee covers the cost of awarding the passes.For more information about the synchronous fireflies, please visit the park website at http://www.nps.gov/grsm/learn/nature/fireflies.htm.