If it has one, it's on the reverse above the bell.
The mint mark on Franklin half dollars is on the reverse side, just above the Liberty Bell.
US Quarters minted in 1954 bear both the mint mark of San Francisco, California mint "S" and the mint mark of the Denver, Colorado mint "D". Additionally, the US Mint at Philadelphia, Pensylvania also struck these quarters but no mint mark was used.
From 1946 to 1964, the mint mark position was at the bottom left of the torch on the back of the coin. No mint mark = Phila. S = San Francisco D = Denver
All Washington quarters dated 1932 to 1964 had the mint mark on the back under the bow of the wreath. No mint mark = Philadelphia D = Denver S = San Francisco (up to 1954)
Franklin half dollars are not rare or even scarce, if the coin has any wear at all value is just for the silver about $12.00.
The mint mark on Franklin half dollars is on the reverse side, just above the Liberty Bell.
No mint mark indicates that the coin was minted in Philadelphia.
1954
US Quarters minted in 1954 bear both the mint mark of San Francisco, California mint "S" and the mint mark of the Denver, Colorado mint "D". Additionally, the US Mint at Philadelphia, Pensylvania also struck these quarters but no mint mark was used.
5 cents.
From 1946 to 1964, the mint mark position was at the bottom left of the torch on the back of the coin. No mint mark = Phila. S = San Francisco D = Denver
The San Francisco Mint did not make any half dollars after 1954. If your coin has a mint mark it must be a D for Denver. In any case as of 06/2008 it's worth about $7 for its silver content.
Franklin halves are very obvious. They all have the same design, a picture of an older Benjamin Franklin on the front and the Liberty Bell on the back. The mint mark position is above the bell: No mint mark = Philadelphia D = Denver S = San Francisco
All Washington quarters dated 1932 to 1964 had the mint mark on the back under the bow of the wreath. No mint mark = Philadelphia D = Denver S = San Francisco (up to 1954)
If it was minted in San Francisco or Denver, there will be a small S or D above the yoke of the Liberty bell. Philadelphia did not use a P mint mark back then, so coins without a mint mark are from that city.
Franklin half dollars are not rare or even scarce, if the coin has any wear at all value is just for the silver about $12.00.
The US never used an E mintmark. The only mintmarks on a 1954 Franklin half would be D (Denver) or S (San Francisco). Philadelphia didn't use a mint mark at that time.There's more information at the Related Question.