Who was the first woman film director to win an Oscar in the United States?

Kathryn Bigelow has so far become the only woman to win the Best Director Oscar for her work on the 2009 film "The Hurt Locker." Sofia Coppola was nominated for Best Director for the 2003 movie, "Lost in Translation." Italian director Lina Wertmüller was nominated for Best Director in 1976 for "Seven Beauties." New Zealand's Jane Campion was nominated for Best Director for "The Piano" in 1993 (she won an Oscar that same year for Best Original Screenplay).