After two weeks of trail work, the members of Civilian Conservation Corps Camp P-66 needed a break.

The year was 1937, and all that remained to complete the Appalachian Trail was a two-mile stretch on Sugarloaf Mountain in central Maine. On Aug. 16, two days after the CCC crew finished this final segment, the crew’s principal foreman sent a letter to Myron Avery, chairman of the Appalachian Trail Conference, saying the project had been completed, and that after resting for a few days, the CCC team would return to the trail to build shelters.

Nowhere in the brief letter is there any mention that after more than 15 years of trail construction involving hundreds of volunteers, the Appalachian Trail was finally finished.

Tuesday marks the 75th anniversary of the completion of the Appalachian Trail, the longest hiking-only footpath in the world. Today, the AT stretches roughly 2,180 miles between Springer Mountain in north Georgia and Mount Katahdin, the highest mountain in Maine. In between, the trail passes through 14 states, with elevations ranging from 6,625 feet atop Clingmans Dome in the Great Smoky Mountains National Park, to 124 feet at the Bear Mountain Bridge across New York’s Hudson River.

Marked by white blazes, the trail cuts through eight national forests, six national parks and numerous state forests as it follows the ridges and valleys of one of the oldest mountain ranges in the world.

The origin of the AT can be traced to a magazine article written in 1921 by Benton MacKaye, a regional planner and forester for the U.S. Forest Service, who argued for the creation of a long-distance hiking trail as an antidote to the rapid industrialization of American society. In 1922, MacKaye’s grand idea was featured in a story in the New York Evening Post that ran under the headline, “A Great Trail from Maine to Georgia!”

In 1923, volunteers with the New York-New Jersey Trail Conference built the first section of the AT about 45 miles north of New York City, and in 1925 the Appalachian Trail Conference — now called the Appalachian Trail Conservancy — was formed to coordinate the volunteer effort that served as the backbone for completing and maintaining the long-distance footpath.

In 1968, the AT was named a National Scenic Trail under the new National Trails System Act. Today, the AT is managed through a unique partnership between the nonprofit Appalachian Trail Conservancy, the National Park Service, the U.S. Forest Service, 31 trail-maintaining clubs, and assorted state and local agencies.

“The Appalachian Trail is a national park, but its day-to-day operations are delegated to us, a not-for-profit organization,” said Mark Wenger, executive director of the Appalachian Trail Conservancy. “From the very beginning it’s been a private-public partnership in various guises. It takes a lot of effort and compromise, but somehow it all holds together.”

An estimated 2 million to 3 million people visit the AT each year. While much of the trail passes through some of the most remote wilderness areas remaining in the eastern U.S., portions of the footpath traverse towns and skirt major metropolitan areas. It’s estimated that two-thirds of the current U.S. population lives within 550 miles of the AT.

Today, the AT is more scenic and in better shape than ever before, despite being heavily used. According to the Appalachian Trail Conservancy, virtually all of the AT’s original route has been relocated or rebuilt to create a corridor that’s 99 percent in public ownership. Roan Mountain, in northeastern Tennessee, wasn’t along the AT route in 1937, nor were Mount Rogers or Grayson Highlands, both in the high country of southwestern Virginia.

The AT’s final two-mile segment on Sugarloaf Mountain in Maine has been relegated to a side trail to keep hikers away from downhill skiers, and in the Great Smoky Mountains National Park — where the AT stretches for 72 miles — trail volunteers have relocated sections between Ekaneetlee Gap and Mollies Ridge; Big Abrams Gap and Little Abrams Gap; Russell and Spence fields; and a short section just east of the park from Davenport Gap to the Pigeon River.

Morgan Sommerville, the Appalachian Trail Conservancy’s southern regional director, said much of the trail rerouting in the Smokies has been aimed at improving water drainage and controlling erosion along the AT.

“The Appalachian Trail in the Smokies is in the best condition since I began working here 30 years ago.” Sommerville said.

This spring, an estimated 2,300 thru-hikers set out from Springer Mountain with the goal of reaching Mount Katahdin. According to the Appalachian Trail Conservancy, that’s a 33 percent increase over the number of thru-hikers who set out last year. Trail officials say the increase is likely due to the mild weather in March, when many northbound thru-hikers set out for Maine.

Latest estimates indicate that 924 of this year’s batch of thru-hikers reported reaching the trail’s unofficial halfway point in Harpers Ferry, W.Va., compared with 772 last year.

In recent years, about 28 percent of the thru-hikers who set out northbound from Georgia in early spring typically make it all the way to Maine. This translates to 500-600 hikers a year who complete the entire AT in one push. In addition to thru-hikers, section hikers complete the AT by hiking it piecemeal.

On average, it takes five to seven months to thru-hike the entire AT. The trail is sprinkled with roughly 250 shelters about a day’s hike — anywhere from eight to 30 miles — apart. Advances in hiking-boot technology and camping equipment may be making trail life a bit more comfortable in modern times, but with an estimated 5 million footsteps over 2,180 miles, the AT still sets one of the world’s most challenging benchmarks in long-distance backpacking.

In 1948, a World War II veteran named Earl Shaffer became the first person to hike the AT in one season. Shaffer’s feat was viewed with strong skepticism by none other than Myron Avery, chairman of the Appalachian Trail Conference from 1931 to his death in 1952, who himself had walked the entire AT, but in sections, not as a thru-hike.

According to Brian King, spokesman for the Appalachian Trail Conservancy, Shaffer was grilled by Avery and other members of the Appalachian Trail Conference who demanded to look at his trail diary and photos.

“Myron (Avery) thought hiking the AT was great for physical fitness, but he never imagined anybody would ever have the desire or the ability walk the whole thing in a single hike,” King said.

In 1965, Shaffer hiked the AT from Maine to Springer Mountain, which recently had replaced Oglethorpe, Ga., as the trail’s southern terminus, making him the first person to complete the trail from Georgia to Maine and Maine to Georgia. In 1998, two weeks before his 80th birthday, Shaffer thru-hiked the AT for the third time.

“Thru-hiking gets a lot of attention, but what I’d like people to keep in mind about the AT is that you don’t have to hike the whole thing,” King said. “It’s really out there for day hikes and weekend trips. It’s a long-distance trail, but it’s a trail in a lot of people’s backyard.”

©2012 the Knoxville News-Sentinel (Knoxville, Tenn.)

Distributed by MCT Information Services