Who was the first woman to serve on the Supreme Court?

Sandra Day O'Connor holds the distinction of being the first woman to serve on the Supreme Court of the United States. Appointed by President Ronald Reagan, she took her seat on the Court in 1981. O'Connor's appointment was a significant milestone in U.S. history, as it marked a major step towards gender equality in the highest levels of government.

Her tenure on the Court was notable for her role in pivotal cases where her moderate conservative views often positioned her as a swing vote. Throughout her career, O'Connor advocated for judicial independence and emphasized the importance of the rule of law. Her groundbreaking position paved the way for future female justices, influencing the diversity of perspectives on the Supreme Court.

The other names mentioned in the options are also prominent justices but came to the Court after O'Connor. Ruth Bader Ginsburg, Sonia Sotomayor, and Elena Kagan all contributed significantly to the judiciary and women's rights, but they did not serve as the first female justice. Ginsburg was appointed in 1993, Sotomayor in 2009, and Kagan in 2010, all following the landmark appointment of O'Connor.