In 1885 Rushmore came to the Black Hills of South Dakota to check the titles to properties for an eastern mining company owned by James Wilson following the 1883 opening of the Etta tin mine.
How Mount Rushmore came to be named after Charles is subject to contradictory recounting, but the United States Board of Geographic Names officially recognized the name in June 1930, five years after Rushmore donated $5,000 (equivalent to $71,433 in 2018) towards Gutzon Borglum's sculpture—the largest single contribution.
The memorial was dedicated by President Calvin Coolidge on August 10, 1927.
Rushmore was a member of the Phi Gamma Delta fraternity and a Freemason.