HANOVER — Strung together over 2,180 miles from Springer Mountain in Georgia to Kathadin in Maine, the Appalachian Trail, or “AT” as it is called, turns 75, next month.

New Hampshire, with 161 miles of the longest footpath, was one of the earliest to connect its trails together. Though they have changed over time, most all of it is now protected from development.

“The AT through the Whites is one of the most popular sections of the 2,100-plus mile trail,” said Rob Burbank, spokesman for the Appalachian Mountain Club.

He said many hikers consider the Granite State’s contribution as some of the most rugged and magnificent along the trail and the first alpine zone encountered each summer by “thru hikers” traveling north, at Mt. Moosilaukee in Warren.

It was envisioned first by Benton MacKaye as a series of ridge line camps along the Appalachian Mountains as a “refuge” from the industrial world. The trail aspect connecting the shelters was considered secondary to him. But as the idea caught on, the trail itself soon became the focus.

The original trail took more than 15 years to build and was completed on August 14, 1937, when the last two miles were completed by the Civilian Conservation Corps on the back side of Maine’s Sugarloaf Mountain.

Now, 99 percent of the trail is conserved as part of a National Park, said Javier Folgar, spokesman for the Appalachian Trail Conservancy, the non-profit organization for the trail, based in Harper’s Ferry, W.V.

New Hampshire, he said, is one of 14 states along the path.

It runs southwest to northeast from Hanover to Gorham and crosses Mounts Cube, Moosilaukee, Washington through the Presidential Range and out towards the Mahoosuc Range in Maine. Most of it is in the White Mountain National Forest.

At the Hanover Inn, which is directly on the trail, thru hikers see a bronze sign letting them know they have 431 miles to go to its end at Katahdin and 1,713 to go if they are headed south to Springer Mountain, Ga.

In New Hampshire, about 70 miles of the trail is maintained by the Dartmouth Outing Club from Vermont up to Route 112 in Woodstock up near Lost River, while the Eastern side of the trail is maintained by the Appalachian Mountain Club.

Jason Berard is an avid hiker and a trail adopter who is also involved in the Upper Valley Land Trust. He said the trail in New Hampshire gets most use from locals, “which is great.”

An estimated 2 to 3 million people visit the AT every year.

AMC maintains 350 miles of the AT, including the entire sections in Connecticut and Massachusetts, and portions in Pennsylvania and Maine.

On these stretches of the AT, AMC cares for 37 campsites and shelters and eight huts, all of which are open for use by the public. To help accommodate AT thru hikers, AMC offers a work-for-stay option at its shelters and huts, said Burbank.

“In these states AMC maintains the trail, shelters and campsites, it monitors the AT corridor to ensure it is well marked and not encroached upon. We do this through a significant and skilled volunteer base in all states, volunteer teen trail crew programs in New Hampshire and Massachusetts, staff trail crew and backcountry campsite caretakers,” he wrote in an email.

Most northbound thru hikers tend to hit the Whites in mid-July.

Berard said the AT is used “not only by hikers, and dog walkers, but by local schools as an outdoor classroom ... but has also come to be seen as an essential corridor for wildlife to move freely, which may be essential with climate change in the years ahead.

“Not only that, but I would say that the corridor is a magnet for further land conservation,” he said.

Throughout the Upper Valley Land Trust, where he is stewardship coordinator, numerous easements abut the AT Corridor.

Maintenance is critical and Berard said is largely accomplished by volunteers.

Last year, the Dartmouth Outing Club alone had more than 500 volunteer hours logged just for basic maintenance on its section of the AT.

A celebration is planned on Aug. 14 at Sugarloaf Resort in Maine with a hike and an opportunity to sign a special register. For information on the event visit www.matc.org.

ptracy@unionleader.com