When President Trump announced in May that he would attend the festivities there, it invited even more scrutiny of the monument’s history, the leaders it celebrates, the sculptor who created it and the land it towers over.

Native Americans have long criticized the sculpture, in part because it was built on what had been Indigenous land. And more recently, amid a nationwide movement against racism that has toppled statues commemorating Confederate generals and other historical figures, some activists have called for Mount Rushmore to close.

During the 1920s, a historian in South Dakota, Doane Robinson, was mulling ideas for a monument that would draw tourists to his state.

Mr. Robinson originally envisioned a sculpture memorializing figures of the American West, such as the explorers Lewis and Clark or the Oglala Lakota leader Red Cloud. But the sculptor who was ultimately chosen for the project, Gutzon Borglum, settled on a concept to pay tribute to four former commanders in chief.

“He picked four presidents he thought represented major accomplishments in the American story,” said Gene A. Smith, a professor of U.S. history at Texas Christian University.

Before he was recruited to create Mount Rushmore, Mr. Borglum had been involved with another project: an enormous bas-relief at Stone Mountain in Georgia that memorialized Confederate leaders.

It was eventually completed without him, but Mr. Borglum formed strong bonds with leaders of the Ku Klux Klan and participated in their meetings, in part to secure funding for the Stone Mountain project. He also espoused white supremacist and anti-Semitic ideas, according to excerpts from his letters included in “Great White Fathers,” a book by the writer John Taliaferro about the history of Mount Rushmore.