MOUNT KATAHDIN, Me. — The storied Appalachian Trail, which begins 2,190 miles away in Georgia, ends here, with a final scramble up Maine’s highest peak — some of it nearly vertical, much of it blocked by boulders. For those who have trekked five or six months, Katahdin’s iconic summit is an exhausting challenge with a rewarding end.

“It takes your breath away,” said Chuck Wood, 64, a hiker from Norristown, Pa. “Just to be there, it’s like an audience with the Lord.”

But that experience is now in jeopardy. Faced with increasing crowds and partylike behavior by a few — including an ultramarathon runner who celebrated at the summit last month with a spray of champagne — officials here are threatening to reroute the end of the trail off Katahdin and out of Baxter State Park.

The very idea has stunned the hiking world. Katahdin has been the trail’s northern terminus for more than 80 years. For the thousands who set out annually to follow its entire path, moving the trail’s endpoint off this rocky peak would be a momentous detour, forcing long-distance hikers to end their treks not with a bang but a whimper.