The Americans will play Great Britain and Ireland on Sept. 6-7 at Ganton Golf Club in North Yorkshire, England. The United States leads the series 31-6-1, but Great Britain-Ireland won in 1999 and 2001.
Williams, a junior at Auburn, reached the U.S. Amateur semifinals, while Zahringer, the reigning U.S. Mid-Amateur champion, made the quarterfinals. Each was eliminated by top-ranked Casey Wittenberg, who was upset by Australia's Nick Flanagan in Sunday's final.
Previously chosen for the U.S. team were Bill Haas, Trip Kuehne, Matt Hendrix, Brock Mackenzie, Ryan Moore, Chris Nallen, Adam Rubinson and Wittenberg. Kuehne is the only previous Walker Cup team member.
Zahringer is the oldest U.S. golfer chosen since 54-year-old Bill Campbell in 1975.
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