Blanchard Springs Caverns

Blanchard Springs Cavern
IUCN category VI (protected area with sustainable use of natural resources)
Speleothems in Blanchard Springs Cavern
Location	Stone County, Arkansas, U.S.
Nearest city	Fifty-Six
Coordinates	35°57′49.26″N 92°10′45.58″W / 35.9636833°N 92.1793278°W / 35.9636833; -92.1793278Coordinates: 35°57′49.26″N 92°10′45.58″W / 35.9636833°N 92.1793278°W / 35.9636833; -92.1793278
Governing body	United States Forest Service

Blanchard Springs Caverns is a cave system located in the Ozark–St. Francis National Forest in Stone County in northern Arkansas, 2 miles off Highway 14 a short distance north of Mountain View. It is the only tourist cave owned by the United States Forest Service and the only one owned by the Federal government outside the National Park System. Blanchard Springs Caverns is a three-level cave system, two of which are open for guided tours. The Dripstone Trail runs through the uppermost level of caverns for about a half-mile and opened in 1973. The Discovery Trail opened in 1977 and loops through a 1.2-mile section of the cavern, descending to the lower level of the cave, 366 feet underground, as well as to the Natural Entrance, about 70 feet below ground at that point, following the stream bed of the springs that created the cavern. This trail includes the Rimstone Dams, which create pools along the stream bed, and the Ghost Room with its huge white flowstone. Also offered is a "Wild Cave" tour which allows access to undeveloped parts of the cave to more adventurous visitors. It follows the upstream section of the cave in the lower levels, continuing beyond where the Discovery Trail ends.

Local residents knew about the cave by the 1930s and called it Half-Mile Cave. The first systematic exploration of the cave began in 1955 and went for five years. Additionally in 1955, explorers discovered a 1,000-year-old Native American skeleton in the cave. The skeleton had a fractured skull, fractured ribs, and a fractured leg. How this explorer entered the cave is unknown. The caverns were opened to the public in 1973 after 10 years of development on the Dripstone Trail. Blanchard Springs Caverns received its name from the cave's source, Blanchard Springs. The springs, in turn, were named for John Blanchard, who owned about 160 acres of land, which would include the later-discovered caverns. Blanchard died in 1914.

With 8.1 miles of surveyed passage, Blanchard is the second longest cave in Arkansas and the largest in volume. The limestone rock from which the caves and their formations developed was laid down in an ancient sea more than 350 million years ago. The cave is in middle Ordovician to lower Mississippian rocks and extends through six stratigraphic formations. The cave has shown over 5 levels of passage development but the upper two levels have eroded away as deepening valleys on the surface cut into them. The cave's formation was largely phreatic in nature (formed below the water table) and passages have elliptical cross-sections typical of these formations. During the cave's development, active streams have been pirated from one level down to another without much vadose erosion occurring. The present stream currently rises from the cave at Blanchard Springs itself, at the same temperature as the cave, a constant, year-round 58 °F (14 °C). Most of the lower-level Discovery Route is in the approximately 100-foot thick Plattin limestone whereas the Dripstone tour route in the uppermost level of the cave spans 3 units, the Boone Chert, Carson Shale, and the Fernvale Limestone. Blanchard remains a "living" cave in part because of the care given by visitors and the United States Forest Service. Thus the formations inside continue to grow as calcite is actively deposited by seeping and dripping water. One of the outstanding examples of formation growth is the Giant Flowstone, one of the largest in the U.S., at 164 feet long, 33 feet wide, and 30 feet thick.