Where are mint marks on US half dollars?

Capped Bust - above the date (1838 and 1839 only). None or O

Seated Liberty - under the eagle. None, D, O, S, CC

Barber - under the eagle. None, D, O, S, CC

Walking Liberty - 1916 and some 1917, on the front under In God We Trust. None, D, S

Walking Liberty - some 1917 and all others, on the back around the 8:00 position.

Franklin - above the bell yoke. None, D, S.

Kennedy - 1964, on the back near the eagle's claw on the left side of the coin.

1965-67 - no mint marks due to the coin shortage.

1968-1979 - above the date; none, D, S

1980-present - above the date; P, D, S

None or P = Philadelphia

S = San Francisco

D = Denver

O = New Orleans

CC = Carson City