Appalachian Trail hikers hoping to finish their 2,190-mile trek on Mount Katahdin this weekend are being asked to make alternate plans.

The Monson Appalachian Trail Visitor Center is advising long-distance hikers to summit Maine’s tallest peak before Saturday, Sept. 1 or after Monday, Sept. 3 to allow the Penobscot Indian Nation to take part in the Katahdin 100, an annual spiritual run that finishes at the northern terminus of the AT.

The Katahdin Stream Campground, located at the base of the AT route up the 5,267-foot mountain in Baxter State Park, will be closed to overnight guests on Saturday and Sunday while the Penobscot conduct their traditional ceremonies.

“Avoiding those days for summiting is in the best interest for the hikers and Baxter and the AT,” Claire Polfus, the program manager of Appalachian Trail Conservancy Maine, told The Bangor Daily News.

Meanwhile, there are no day-use parking passes left for either Saturday or Sunday, the Monson Visitor Center announced in a Facebook post. The visitor center staff added that The Birches campground will remain open to 12 northbound hikers, but the area will be exceedingly busy.

The Katahdin 100, which was first run in the early 1980s, retraces the migration pattern of Maine’s native peoples from Indian Island near Orono to Mount Katahdin. Each year, the members of the Penobscot tribe make the 100-mile journey from Indian Island to the mountain in canoes, on bikes, and their own two feet.

“For the duration of the gathering (Saturday to Monday of Labor Day weekend), Katahdin Stream Campground largely belongs to the Penobscot.” the visitor center staff wrote on Facebook. “It’s important to remember…this was Penobscot territory for millennia before the A.T. existed.”