Supporters say the man who dominated American and global politics in the eighties deserves to take his place alongside the presidents who shaped the United States.
But opponents say the addition would damage the rockface and destroy a great work of art.
![[ image: width=150]](/olmedia/285000/images/_288213_reagan150.jpg)
The proposal to carve Mr Reagan's face into the South Dakota sculpture comes up for debate in the US Congress this week.
Mount Rushmore features the heads of four presidents - George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt.
Sculptor Gutzon Borglum began his monument to American history in 1927. It took another 14 years to complete with workmen having to blast through 100 foot of rock.
A great president
Republican Congressman Matt Salmon, who is backing the proposal, says Mr Reagan should be added because he gave Americans faith in the future.
![[ image: width=150]](/olmedia/285000/images/_288213_rush150.jpg)
''He's the president that ended the Cold War. You think about 40 years of a major threat, not only to our country but to the world at large, being ended by one man - that's quite an achievement.''
But park rangers say there is no room for another head and the addition would endanger the already fragile structure.
Former head of maintenance Eugene Koeving, who knew Mr Borglum, says Mr Reagan's face would also destroy the monument's artistic value.
''Would you take some of Michaelangelo's work and add to it?
''This is one of the most beautiful pieces of artwork in the world, and to go ahead now and change it from the original carving would absolutely desecrate it,'' he added.
Elvis Presley
BBC Washington Correspondent Philippa Thomas says congressmen are unlikely to approve the plan.
Previous suggestions to add John F Kennedy and Elvis Presley have got short shrift.
It seems Mr Reagan will have to console himself with other memorials in his name - a motorway, an airport and an office development.
Mount Rushmore
Ronald Reagan
Ronald Reagan: US Presidents
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