Gardiner’s population of less than 900 will swell considerably this summer when a crowd gathers to celebrate the 100th anniversary of the National Park Service on Aug. 25.

“We’re setting the stage for the second century,” said Bill Berg, a Gardiner resident and businessman involved in the celebration.

The town that sits tight on Yellowstone National Park’s northern border is even being gussied up for the affair, part of a $16.5 million project to turn the stone Roosevelt Arch into a pedestrian-only area, create more parking for visitors and build a visitor center. The arch gets its name from former President Theodore Roosevelt who dedicated the structure in 1903.

“Last year was a whole lot of digging and disruption,” Berg said. “Phase One will be wrapped up by Aug. 25.”

That includes the installation of a small stage in Arch Park where musicians Emmylou Harris and John Prine are scheduled to give a free concert on Aug. 25 at 7 p.m. Berg predicts attendance at the event will top 5,000. The concert will be streamed live online to widen its reach.

“This very special event will kick off the second century for the National Park Service, highlight the importance of public/private partnerships, and recognize the completion of the Gardiner Gateway Project Phase One,” said Dan Wenk, Yellowstone National Park superintendent, in a press release.

The concert will also include Leyla McCalla, the children’s chorus The Singing Angels from Cleveland, Ohio, and Teddy Roosevelt reenactor, Joe Wiegand, with more performances and details to be announced. Local, state, and national dignitaries will also speak at the event.

“The venue is limited so we’re trying to manage expectations while doing the best to have a meaningful event,” Berg said.

“There’s more news coming, too,” he added, although Berg declined to give any hints. Last year, however, he made it clear that he’d like President Barack Obama to attend the festivities, but wouldn’t confirm that was the next announcement.

All of the work is a considerable upgrade from the access available when Yellowstone was named the first national park in 1872. Back then “only a trail suitable for saddle and pack trains ... provided some visitors and supplies access to the Mammoth Hot Springs area” from Gardiner, according to the environmental assessment completed for the work. “In 1884, Army Corp of Engineers Lt. Dan Kingman constructed a new (and the current) alignment between the town of Gardiner and the park headquarters at Mammoth Hot Springs. But it was not until the construction of the Roosevelt Arch in 1903 that the road was constructed from the vicinity of the current North Entrance Station to the Roosevelt Arch.”

Because traffic into the park was originally routed through the Roosevelt Arch, a hairpin curve drivers had to negotiate on Park Street in Gardiner to drive through the arch meant traffic would often get backed up as tourists stopped to take photographs. With the redesign, that won’t be a problem.

Last year, almost 65,000 vehicles passed through the North Entrance at Gardiner just in July, the busiest month of a year that set a new record high for visitation — more than 4 million tourists. Many predict that if gas prices remain low and with all of the interest in Yellowstone generated by the Park Service centennial, that visitation could be even higher this year.

Advance tickets for the concert are required. Tickets are free, but limited. The first tickets were released on May 15. Additional ticket releases will occur on June 15 and July 15 at https://www.ticketriver.com/event/19359.

No alcohol, coolers, umbrellas, or dogs will be allowed at the celebration. For more information, visit https://www.nps.gov/yell/planyourvisit/evening-arch.htm.