The 1917-D Walking Liberty Half Dollar is a major collectible key/semi-key date in the series because the Denver Mint struck two distinct varieties during this single year: Obverse Mint Mark and Reverse Mint Mark.
In early 1917, the U.S. Mint placed the mint mark on the obverse (front) below the national motto "IN GOD WE TRUST". Partway through production, officials decided to move the mint mark to the reverse (back) near the bottom-left rim below the pine branch.
| Variety | Mint Mark Location | Mintage | Collector Demand / Value |
| 1917-D Obverse | Front (below "IN GOD WE TRUST") | 765,400 | Key Date — High demand & substantial premium |
| 1917-D Reverse | Back (bottom left near rim) | 2,520,000 | Semi-Key — Common in low grades, valuable in MS |
| Attribute | Specification |
| Issuer | United States Mint (Denver — D mint mark) |
| Designer | Adolph A. Weinman |
| Denomination | 50 Cents ($0.50 USD) |
| Year | 1917 |
| Composition | 90% Silver, 10% Copper |
| Fine Silver Content | 0.36169 troy oz |
| Weight | 12.50 g |
| Diameter | 30.63 mm |