The mint mark for all Lincoln cents can be found directly below the date. Philadelphia has no mint mark, D is Denver, and S is San Francisco.
A US Lincoln cent without a mintmark was made in Philadelphia, no one cent coin has a P mintmark. 1955 is a common date wheat cent, most are 2 to 5 cents.
A 1943 steel penny with no mintmark can be worth $.35 - $1.50
A 1941 penny without a mintmark means it was minted in Philidelphia.
A US Lincoln cent with no mintmark was made in Philadelphia.
Average value is 3 to 10 cents.
If it has one , it's under the date
An Australian 1956 Penny looks almost exactly the same as any other Australian Penny minted from 1955 to 1964 inclusive. A 1956 Penny minted in Perth will have a mintmark (.) after the "Y" in PENNY (Y.). The Melbourne Penny has no mintmark. See the 1964 penny at the link below.
A US Lincoln cent without a mintmark was made in Philadelphia, no one cent coin has a P mintmark. 1955 is a common date wheat cent, most are 2 to 5 cents.
Some rare U.S. pennies are: 1943 copper cents, 1922 no mintmark cents and the 1955 doubled die cents.
Australian Pennies from 1955 to 1964 inclusive were minted at either or both of the Melbourne Mint and the Perth Mint. Pennies minted at the Melbourne Mint have no mintmark. 1956 Pennies minted at the Perth Mint can be identified by a dot "." after the "Y" in PENNY, eg. "PENNY.".
There is no mintmark on the 1921 British Penny, they were all minted at the Royal Mint London.
A mintmark is a small identification mark used to tell which mint it was made in.
underneath the year
It will have a S mintmark.
Australia struck pennies in 1955 at two locations - the Melbourne Mint and the Perth Mint. The Perth Mint pennies have a very small dot, to the right and in line with the base of the "Y" in "PENNY" on the reverse / tails side. The pennies struck at the Melbourne Mint do not have this dot.
An Australian Penny or Halfpenny with a "Y." (PENNY.) mintmark indicates that the coin was minted at the Perth Mint. An Australian Penny or Halfpenny with a "I" mintmark indicates that the coin was minted at either the Calcutta or Bombay Mints in India.
Philadelphia. Cents (pennies) from the Philadelphia mint have never carried a mintmark.