The mintmark is on the reverse of the coin underneath the "One" in "One Dollar"
1928 makes it a Peace dollar. The mint mark is located on the reverse (tails) side, below the word "one." D for Denver, S is San Francisco, and no mark is Philadelphia.
Denver did not strike any dollars in 1928. You may be seeing a small and indistinct S mint mark. Check the Related Question for more details.
No D's in 1928. The coins were only struck in Philadelphia and San Francisco. The S coins run from $30.00 to $70.00 in circulated grades.
The Denver mint did not strike any silver dollars in 1928. You may have a 1928-S where the S is indistinct. This coin is worth $20 to $30 depending on condition.
On a 1928 Peace Silver Dollar, the mint mark is located on the lower right side of the reverse, just above the tail of the eagle. If the coin has a "V" instead of "U" in the word "PLURAL," it indicates it is a variety known as the "V" mint mark version. The mint mark itself indicates where the coin was minted: "S" for San Francisco, "D" for Denver, and no mint mark for Philadelphia.
There were no dollar coins minted in 1992.
42cents
About $27.
1892 Liberty silver dollar mint mark in on the reverse just above and between the D and O in Dollar at the bottom of the coin. Mine is marked with an S.
San Francisco
Your 1928 eagle silver dollar is actually a 1928 PEACE dollar, the first Silver Eagle bullion coin was made in 1986. But for this year of issue Peace dollar it's very important to see if there is a mintmark (S) on the reverse just above the eagles tail it makes a big difference in value. If you see the S a low value for the coin is $16.00 no S low value is $250.00. Take it to a dealer or collector for an assessment
The 1928 Philadelphia Peace Dollar has no mint mark, indicating it was minted in Philadelphia. A normal 1928 Peace Dollar would have a D or S mint mark denoting it was minted in Denver or San Francisco. The absence of a mint mark on the coin indicates it is the Philadelphia Mint version.