Question: Are Jeff Buckley and Cave In both from the United States?

Context articles: Jeff Buckley
Blowhole Cave
Civil Twilight (album)
Gap Cave
Reid Buckley
Cave In
Indian Caverns
Ed Harcourt
Eagle Cave
Wind Cave National Park

Jeffrey Scott "Jeff" Buckley (November 17, 1966 – May 29, 1997), raised as Scott Moorhead, was an American singer-songwriter and guitarist.
 After a decade as a session guitarist in Los Angeles, Buckley amassed a following in the early 1990s by playing cover songs at venues in Manhattan's East Village, such as Sin-é, gradually focusing more on his own material.
 After rebuffing much interest from record labels and his father Tim Buckley's manager Herb Cohen, he signed with Columbia, recruited a band, and recorded what would be his only studio album, "Grace", in 1994.
 In 2004, "Rolling Stone Magazine" listed him at number 39 on their list of greatest singers of all time.
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 In the December 2013 Mojo, Grace was named the 12th best album of the magazine's 20-year lifetime.
Blowhole Cave is a cave in Utah County, Utah, United States to the west of Utah Lake.
 The cave is owned by the Utah School and Institutional Trust Lands Administration (SITLA) and is managed by the Timpanogos Grotto of the National Speleological Society.
 A cave gate was installed April 25–26, 2006.
 Blowhole cave is very warm (more than 80 F ) and moist.
 Total surveyed length is 1165 ft , and total depth is 340 ft .
 Blowhole Cave is the 9th deepest cave in Utah.
 To explore the cave, approximately 400 ft of rope is needed.
 The most notable formation inside the cave is the Navajo Blanket, a wall composed of brown, tan, red, white, and gray rock.
Civil Twilight is the debut studio album of Civil Twilight.
 It was officially released 6 April 2010 in South Africa and on 13 April 2010 in the United States and United Kingdom.
 It features many alternative rock and classical influences.
 Many have drawn parallels between the band's debut and the early work of U2 along with Muse.
 Steven McKellar's vocals have been compared to that of Radiohead's Thom Yorke and Jeff Buckley.
 During its original independent release by the band in 2007, the album was originally titled "Human".
Gap Cave is located just underneath Pinnacle Overlook in the Cumberland Gap National Historical Park, Lee County, Virginia.
 Currently, the cave has a surveyed length of 18.5 miles and is the 42nd longest cave in the United States and 154th in the world.
 There are six known entrances: the Gap Cave Entrance (also known as the King Solomons Cave Entrance), an artificial entrance, known as the Cudjo's Cave Entrance, the Stream Entrance, the Soldiers Cave Entrance, the Big Saltpeter Cave Entrance, and the Wellhole.
 All lead into the same cave, Gap Cave.
Fergus Reid Buckley (July 14, 1930 – April 14, 2014) was an American writer, speaker, and educator.
 Among his books is a history of his family, "An American Family—The Buckleys" (2008), which primarily focuses on his father, William Frank Buckley, Sr. Reid's brother, William F. Buckley, Jr., is the best known member of the family.
 He graduated from Yale University in 1952, where he was a member of Skull and Bones.
 He was born in Paris, France, where his father worked in the oil industry.
 Buckley's older brother was former New York Conservative United States Senator James L. Buckley, and his nephews were writer Christopher Buckley, and Media Research Center founder L. Brent Bozell III.
Cave In is an American rock band that formed in 1995, in Methuen, Massachusetts.
 After several members changes in the late 1990s, their lineup solidified with the 1998 release of "Until Your Heart Stops" through Hydra Head Records.
 Their early albums were prominent in the metalcore scene.
 After this release, the band started experimenting with other genres.
 Cave In later received mainstream recognition for their 2003 RCA Records album "Antenna" and its lead single "Anchor," which had an overall alternative rock style.
 The group went on hiatus in 2006 and later reformed in 2009 with the release of a new EP, "Planets of Old", as well as a new LP in 2011, titled "White Silence".
 Both of these post-hiatus releases saw a return to Cave In's earlier and heavier sound.
Indian Caverns is a show cave in Spruce Creek, Pennsylvania, United States.
 It is a horizontal karst cave of Ordovician Nealmont/Benner limestone, estimated to be about 500,000 years old.
 It is the second-largest cave in Pennsylvania and the largest limestone cave.
 Indian Caverns consists of two sections, originally separated by a 14-foot wall: the "Historic Cave" and the "Giant's Hall".
 The "historic" part of the cave is generally low-ceilinged and closer to the surface (as shallow as 15 ft) with a couple of wide rooms and extensive speleothem formation.
 The Giant's Hall area consists of several large passageways, up to 60 feet high, but with fewer speleothems - though it does include the largest sheet of flowstone in the northeast and a substantial rimstone pool.
 The lowest point of the cave is approximately 140 feet beneath the surface and the cave temperature is a constant 56 degrees Fahrenheit (13 degrees Celsius).
Ed Harcourt is an English singer-songwriter.
 To date, he has released six studio albums, two EPs, and thirteen singles.
 His debut album, "Here Be Monsters", was nominated for the 2001 Mercury Prize.
 Since 2007 he has been writing for other artists, including Sophie Ellis-Bextor, Paloma Faith and performed with Marianne Faithfull and the Libertines.
 His music is influenced by Tom Waits, Nick Cave, and Jeff Buckley, among others.
Eagle Cave is an onyx cave located near Blue River, Wisconsin, in Richland County, Wisconsin, United States.
 Eagle Cave is known as Wisconsin's largest onyx cave and was the first cave to be commercially owned and operated in Wisconsin.
 The cave was discovered in 1849 and opened to the public in 1938.
 It is a popular camping destination, especially during the fall, winter, and spring months, when youth group campers are allowed to camp inside the cave and participate in their cave exploratory program.
 The cave exploratory program has been operating since 1954.
Wind Cave National Park is a United States national park 10 mi north of the town of Hot Springs in western South Dakota.
 Established in 1903 by President Theodore Roosevelt, it was the seventh U.S. National Park and the first cave to be designated a national park anywhere in the world.
 The cave is notable for its displays of the calcite formation known as boxwork.
 Approximately 95 percent of the world's discovered boxwork formations are found in Wind Cave.
 Wind Cave is also known for its frostwork.
 The cave is also considered a three-dimensional "maze cave", recognized as the densest (greatest passage volume per cubic mile) cave system in the world.
 The cave is currently the sixth-longest in the world with 140.47 mi of explored cave passageways.
 Above ground, the park includes the largest remaining natural mixed-grass prairie in the United States.