STURGIS, S.D. – When folks around here say the Sturgis Motorcycle Rally doubles the population of South Dakota, it’s only a slight exaggeration. More than 500,000 bikers invade the Black Hills each August; 776,000 people live in the state.

As the influx revs up this week, so does the tension that has been mounting for several years between the party-hearty biker culture and Native Americans trying to preserve their religious traditions. It came to a boil this year when Arizona entrepreneur Jay Allen started building what he proudly calls the world’s biggest biker bar just two miles from Bear Butte, one of the most sacred sites of the Plains tribes.

“Imagine sitting in a church or sitting in a synagogue, trying to have a … prayer service, and you have half a million bikes running by every minute of the day and night for three weeks,” said Debra White Plume, a Lakota Sioux from the nearby Pine Ridge Indian Reservation. “That’s what the Sturgis Motorcycle Rally does to this environment.”

White Plume is one of the organizers of a monthlong prayer vigil at Bear Butte, a volcanic formation just a few miles east of Sturgis. Since July 4, several hundred Native Americans have been camped at the foot of the hill they revere as the North American equivalent of Mt. Sinai.

The way they see it, the roar of the drag pipes and the drunken revelry emanating from the cavernous biker bars and open-air concert venues threaten the sanctity of their holy ground.

The campers have been praying, fasting and seeking divine guidance on how best to protect the mountain. This week they were joined by representatives of other indigenous peoples – from Canada, Latin America and other parts of the U.S. – whose sacred sites are similarly threatened by commercial or political developments.

The protesters are demanding a five-mile buffer zone around Bear Butte with no alcohol sales and no concert venues.

Organizers say they are not trying to stop the rally, which runs from next Monday through Aug. 13 this year, and they don’t have anything against bikers.

“Bikers are involved only because, as they move out from Sturgis, they’re moving their parties closer to our mountain,” said Nick Tilsen of the Lakota Action Network. “If it was any other kind of development, we’d oppose that too.

“This is about preserving our way of life and protecting our land.”

But John “Brother Speed” Finlay, a biker who works security for Allen’s bars, argued, “Man has no right to be selfish and say it’s just mine, when it’s everybody’s.”

“You just can’t stop the wheels of progress,” added Finlay.

The Meade County commissioners have said land owners have a right to use their property as they see fit, and the commission had no grounds to deny beer and liquor licenses to a number of businesses near Bear Butte that cater to the thirsty visitors.

Much of the local economy depends on the annual influx of bikers: Many businesses remain shuttered for all but a few weeks a year. Even the famous Broken Spoke Saloon, Allen’s original biker bar in Sturgis, opens in mid-July and closes in mid-August.

On Friday, Allen’s bigger and better Broken Spoke – part of a 600-acre site that includes a campground – is scheduled to open within sight of Bear Butte.

“The motorcycle venue is moving very, very close to the mountain,” said Charles Rambow, who served as a ranger in Bear Butte State Park for 30 years. “They’re going to have the biggest biker bar – with people from all over the country coming to provide live entertainment – just a mile and half from the mountain.”

Allen confirmed Wednesday that construction crews are putting final touches on a 22,500-square-foot bar that will have continuous live music for the visitors at his new Sturgis County Line Campground. Plans for the future include more bars, more RV hookups, and a 30,000-seat amphitheater overlooking Bear Butte.

But Allen said the concert stage – and the sound system – will face away from the mountain. What’s more, he said, there are thousands of acres between his land and the butte.

“I really think, in time, these people will realize that they overreacted out of fear.” Allen said, “We’re going to watch sunsets together some day.”