What gold coin has the highest face value?

The highest denomination US coin produced for circulation was the $20 gold piece, often call a Double Eagle, which was produced in various designs between 1849 and 1933.

A $50 gold coin was produced for the Panama-Pacific Exposition in 1915, but it was produced as a commemorative coin and, while legal tender, was not intended to circulate.

Since 1986, $25 and $50 gold coins have been produced by the US Mint. While legal tender, they contain, respectively, 1/2 troy ounce and 1 troy ounce of gold (and thus have a metal value roughly 20 times that of the nominal face value), and are intended for bullion or collectors rather than for circulation.

Since 1997, the mint has also produced $25, $50 and $100 coins in platinum - again, the metal value is several times the nominal face value, and these coins too are primarily intended to be a convenient way of holding bullion.