The last surviving US combat flag flown during the Vietnam War could make $10,000-20,000 on May 24-25.
It will sell at Alexander Historical Auctions in Maryland.
The flag was returned to America by a Colonel McCoid (1923-2000), who served in Vietnam between 1966 and 1973.
The colonel was the last US soldier out of Vietnam (excluding those who remained stationed in Saigon) at the end of the war.
He was billeted in DaNang, where he oversaw peace negotiations between leaders of the North and South Vietnamese forces.
The flag was sold in an auction of his estate and is consigned directly from the buyer.
The lot includes a pair of certificates Vietnam's acting president presented to McCoid and a blue and red 2nd infantry division arm patch McCoid probably wore in Korea.
The auction house describes the flag as "a historic relic from a war which still stirs controversy at its very mention."
Historic American flags are popular collectors' items and have achieved spectacular sums at auction in the past.
Examples have included fragments from the original star spangled banner, which made $67,000 at Heritage in 2011.
The eclectic sale will also include a cane Charlie Chaplin used onscreen in his 1931 movie City Lights. The lot comes from the collection of talk show host Joe Franklin.
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