Question: The White Mountain National Forest includes over 100 miles of which marked hiking trail?
Context: Round Mountain National Recreation Trail is a hiking trail in Roosevelt National Forest west of Loveland, Colorado.  The trail was designated a National Recreation Trail in 1981. The Lone Star Hiking Trail (LSHT) is a hiking trail 96 miles long with an additional 32 miles of loop and crossover trails of "foot-path only" trails.  Located in the Sam Houston National Forest it is the longest continuous hiking trail in the State of Texas.  The trail starts just South of Richards, Texas and ends North-West of Cleveland, Texas. The White Mountain National Forest (WMNF) is a federally managed forest contained within the White Mountains in the northeastern United States.  It was established in 1918 as a result of the Weeks Act of 1911; federal acquisition of land had already begun in 1914.  It has a total area of 750852 acre (1,225 sq mi).  Most of the WMNF is in New Hampshire; a small part (about 5.65% of the forest) is in the neighboring state of Maine.  While often casually referred to as a park, this is a National Forest, used not only for hiking, camping, and skiing, but for logging and other limited commercial purposes.  The WMNF is the only National Forest located in either New Hampshire or Maine.  Most of the major peaks over 4,000 feet high for peak-bagging in New Hampshire are located in the National Forest.  Over 100 mi of the Appalachian Trail traverses the White Mountain National Forest.  In descending order of land area the forest lies in parts of Grafton, Coos, and Carroll counties in New Hampshire, and Oxford County in Maine. Hiking trail of the Piusa River of RMK (State Forest Management Centre) is a 15 kilometre long hiking trail past Vana-Vastseliina castle ruins along the primeval valley of the Piusa River up to Lindora village in Estonia.  The trail is marked by wooden signposts and information boards that introduce the sights.  There are two campfire sights on the trail supplied with barbecue grills and with the possibility of camping.  There are two picnic tables with shelters and a dry toilet.  The hiking trail is situated on Piusa River Valley Landscape Protection Area and among the most interesting sights on the trail are castle ruins, sandstone outcrops Härma Mäemine wall or Keldri wall (highest sandstone outcrop in Estonia), Härma alumine wall or Keldri wall and several old mill places.  There are altogether 12 sandstone outcrops on the hiking trail. The Appalachian National Scenic Trail, generally known as the Appalachian Trail or simply the A.T., is a marked hiking trail in the Eastern United States extending between Springer Mountain in Georgia and Mount Katahdin in Maine.  The trail is about 2,200 miles (3,500 km) long, though the exact length changes over time as parts are modified or rerouted.  The Appalachian Trail Conservancy claims that the Appalachian Trail is the longest hiking-only trail in the world.  More than 2 million people are said to do at least one day-hike on the trail each year. The Alaska Basin Trail is a 7.5 mi long hiking trail in Grand Teton National Park and Bridger-Teton National Forest in the U.S. state of Wyoming.  The trail begins at a junction on the Death Canyon Trail near the Death Canyon Barn and climbs steeply to Static Peak Divide.  From the divide, the trail soon splits with a western branch descending into Alaska Basin and the eastern trail (also known as the Alaska Basin Shelf Trail) continuing north to junction with the Teton Crest Trail.  There are no camping zones on the trail within Grand Teton National Park, however in National Forest lands within Alaska Basin, camping is permitted anywhere more than 200 ft away from lakes, though no open fires are allowed.  The Alaska Basin Trail is oftentimes used by climbers attempting to make ascents of Buck Mountain and Veiled Peak. Bridger National Forest was first established by the U.S. Forest Service on July 1, 1911 in Wyoming with 577580 acre from part of Bonneville National Forest.  On May 14, 1923 Bridger was transferred Wyoming National Forest, and the name was discontinued.  On March 10, 1943 Wyoming was renamed Bridger.  In 1973 Bridger National Forest was administratively combined with Teton National Forest, creating Bridger-Teton National Forest.  In descending order of land area, Bridger National Forest lands are located in Sublette, Lincoln, Fremont, and Teton counties.  There are local ranger district offices in Afton, Big Piney, Kemmerer, and Pinedale.  Its administrative headquarters reside in Jackson, Wyoming as part of the combined Bridger-Teton National Forest.  Its current area of 1,736,075 acres (7,025.65 km²) represents 51.02% of the combined Bridger-Teton's area of 3,402,644 acres (13,770.01 km²).  The forest includes all of the National Wilderness Preservation System's officially designated Bridger Wilderness. The White Mountain Trail is a National Scenic Byway in the U.S. state of New Hampshire.  It travels through the heart of the White Mountains crossing three major mountain passes.  The Trail includes sections of US 3 and US 302, between Lincoln and Conway, connecting at both ends with the Kancamagus Highway (part of NH 112).  It also includes a branch which travels south from Bartlett to the Kancamagus over Bear Notch.  The byway is primarily in the White Mountain National Forest but also traverses Franconia Notch State Park and Crawford Notch State Park.  The White Mountain Trail was designated on June 9, 1998 and is approximately 100 mi long.  Despite the name, it is a scenic byway accessible by car and not a hiking trail. Greyrock Mountain National Recreation Trail is a hiking trail in Roosevelt National Forest west of Laporte, Colorado.  The trail was constructed by the Civilian Conservation Corps in the 1930s and designated as a National Recreation Trail in 1979. The Cibola National Forest (pronounced SEE-bo-lah) is a 1,633,783 acre (6,611.7 km2) United States National Forest in New Mexico, USA.  The name Cibola is thought to be the original Zuni Indian name for their pueblos or tribal lands.  The name was later interpreted by the Spanish to mean, "buffalo."  The forest is disjointed with lands spread across central and northern New Mexico, west Texas and Oklahoma.  The Cibola National Forest is divided into four Ranger Districts: the Sandia, Mountainair, Mt. Taylor, and Magdalena.  The Forest includes the San Mateo, Magdalena, Datil, Bear, Gallina, Manzano, Sandia, Mt. Taylor, and Zuni Mountains of west-central New Mexico.  The Forest also manages four National Grasslands that stretch from northeastern New Mexico eastward into the Texas Panhandle and western Oklahoma.  The Cibola National Forest and Grassland is administered by Region 3 of the United States Forest Service from offices in Albuquerque, New Mexico.  Elevation ranges from 5,000 ft (1,500 m) to 11,301 ft (3,445 m).  (The preceding figures do not include any of the four National Grasslands mentioned below, which are detailed in their individual articles.)  The descending order of Cibola National Forest acres (not counting the three Grassland areas) by county are: Socorro, Cibola, McKinley, Catron, Torrance, Bernalillo, Sandoval County, New Mexico, Lincoln, Sierra, and Valencia counties in New Mexico.  The Cibola National Forest currently has 137,701 acres designated as Wilderness.  In addition to these acres, it has 246,000 acres classified as Inventoried Roadless Areas pursuant to the Roadless Area Conservation Rule.
Answer: Appalachian Trail