Mount Rushmore National Memorial is centered on a sculpture carved into the granite face of Mount Rushmore in the Black Hills in Keystone, South Dakota. Sculptor Gutzon Borglum created the sculpture's design and oversaw the project's execution from 1927 to 1941 with the help of his son Lincoln Borglum. The sculpture features the 60-foot (18 m) heads of Presidents George Washington (1732–1799), Thomas Jefferson (1743–1826), Theodore Roosevelt (1858–1919), and Abraham Lincoln (1809–1865), as recommended by Borglum. The four presidents were chosen to represent the nation's birth, growth, development, and preservation, respectively. The memorial park covers 1,278.45 acres (2.00 sq mi; 5.17 km2) and is 5,725 feet (1,745 m) above sea level.