Why are there certain US Presidents on Mt Rushmore?

The Presidents are Washington, Jefferson, Lincoln, and Theodore Roosevelt.

They were selected by Gutzon Borglum, the sculptor, for their important contributions to the US. George Washington was chosen because he was the father of our country. Thomas Jefferson was honored for the Declaration of Independence, and for the expansion of the nation by the Louisiana Purchase. Teddy Roosevelt was chosen because he saw through the completion of the Panama Canal, and made the US a world power. Lincoln was chosen for preserving the Union through the Civil War.