[3][4] The sculpture features the 60-foot-tall (18 m) heads of four United States presidents: George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln,[5] chosen to represent the nation's birth, growth, development, and preservation.

[6] Mount Rushmore attracts more than two million visitors annually[1] to the memorial park which covers 1,278 acres (2.00 sq mi; 5.17 km2).

Each president was originally to be depicted from head to waist, but lack of funding forced construction to end on October 31, 1941,[13] and only Washington's sculpture includes any detail below chin level.

[15] Mount Rushmore and the surrounding Black Hills (Pahá Sápa) are considered sacred by Plains Indians such as the Arapaho, Cheyenne, and Lakota Sioux, who used the area for centuries as a place to pray and gather food, building materials, and medicine.

[16] The Lakota called the mountain "Six Grandfathers" (Tȟuŋkášila Šákpe),[17] symbolizing ancestral deities personified as the six directions: north, south, east, west, above (sky), and below (earth).

[16] In 1923,[27][28] the Secretary of the South Dakota State Historical Society, Doane Robinson, who would come to be known as the "Father of Mount Rushmore",[18][29] learned about the "Shrine to the Confederacy", a project to carve the likenesses of Confederate generals into the side of Stone Mountain, Georgia, that had been underway since 1915.

[27] On August 20, 1924, Robinson wrote to Gutzon Borglum, the sculptor of "Shrine to the Confederacy", asking him to travel to the Black Hills region to determine whether the carving could be accomplished.

[27] On August 14, 1925, Borglum summitted Black Elk Peak while scouting alternative locations,[26] and reportedly said upon seeing Mount Rushmore, "America will march along that skyline.

"[31] He chose Mount Rushmore, a grander location, partly because it faced southeast and enjoyed maximum exposure to sunlight.

[30] The Lakota and other local indigenous communities objected to the overall plan as constituting desecration of their sacred lands, and to the racist and sometimes violent anti-indigenous policies of the four presidents depicted.

"[34] Senator Norbeck and Congressman William Williamson of South Dakota introduced bills in early 1925 for permission to use federal land,[35] which passed easily.

South Dakota legislation had less support, only passing narrowly on its third attempt, which Governor Carl Gunderson signed into law on March 5, 1925.

Congress passed the Mount Rushmore National Memorial Act, signed by Coolidge, which authorized up to $250,000 in matching funds.

[31][30] The carving of Mount Rushmore involved the use of dynamite, followed by the process of "honeycombing", where workers drill holes close together, allowing small pieces to be removed by hand.

[31] The chief carver of the mountain was Luigi Del Bianco, an artisan and stonemason who emigrated to the U.S. from Friuli in Italy and was chosen to work on this project because of his understanding of sculptural language and ability to imbue emotion in the carved portraits.

[1] The popularity of the location, as with many other national monuments, derives from its immediate recognizability; "there are no substitutes for iconic resources such as the Statue of Liberty, the Lincoln Memorial, or Mount Rushmore.

[61] However, Mount Rushmore also provides access to a surrounding environment of wilderness, which distinguishes it from the typical proximity of national monuments to urban centers like Washington, D.C., and New York City.

[62] Borglum originally envisioned a grand Hall of Records where America's greatest historical documents and artifacts could be protected and shown to tourists.

In 1998, a repository was constructed inside the mouth of the cave housing 16 enamel panels with biographical and historical information about Mount Rushmore as well as the texts of the documents Borglum wanted to preserve there.

[67] Other efforts to conserve the monument have included replacement of the sealant applied originally to cracks in the stone by Gutzon Borglum, which had proved ineffective at providing water resistance.

[70] Terrestrial mammals include the mouse, least chipmunk, red squirrel, skunk, porcupine, raccoon, beaver, badger, coyote, bighorn sheep, bobcat, elk, mule deer, yellow-bellied marmot, and American bison.

[79][77] The National Park Service also reported that at least 27 forest fires around Mount Rushmore in that same period (1998 to 2009) have been caused by fireworks displays.

[82] Coarse grained pegmatite dikes are associated with the granite intrusion of Black Elk Peak and are visibly lighter in color, thus explaining the light-colored streaks on the foreheads of the presidents.

[31] The mountain's height of 5,725 feet (1,745 m) above sea level[8] made it suitable, and because it faces the southeast, the workers also had the advantage of sunlight for most of the day.

[92][98] The Treaty of Fort Laramie (1868) had granted the Black Hills to the Lakota people in perpetuity, but the United States took the area from the tribe after the Great Sioux War of 1876.

Members of the American Indian Movement led an occupation of the monument in 1971, naming it "Mount Crazy Horse", and Lakota holy man John Fire Lame Deer planted a prayer staff on top of the mountain.

Lame Deer said that the staff formed a symbolic shroud over the presidents' faces "which shall remain dirty until the treaties concerning the Black Hills are fulfilled.

[113] In music, American composer Michael Daugherty's 2010 piece for chorus and orchestra, "Mount Rushmore", depicts each of the four presidents in separate movements.

The piece sets texts by George Washington, William Billings, Thomas Jefferson, Maria Cosway, Theodore Roosevelt, and Abraham Lincoln.

[115][116] The Washington Nationals baseball club uses large foam rubber depictions of the "Rushmore Four" in both their marketing campaigns and in a series of in-stadium promotions such as the Presidents Race.