Sandra Day O'Connor was the first woman to serve as a Justice on the United States Supreme Court. Her appointment in 1981 by President Ronald Reagan broke the gender barrier that had existed for over 190 years on the highest court in the United States. In addition to her groundbreaking appointment, Justice O'Connor had a distinguished legal career and contributed significantly to women's rights.

Sandra Day O'Connor was born in El Paso, Texas, in 1930. She grew up on a cattle ranch and was raised in a family that placed a high value on education. She attended Stanford University and graduated with a degree in economics. She then attended Stanford Law School, where she graduated in 1952.

After law school, O'Connor struggled to find a job in a law firm due to her gender. She eventually found work as a deputy county attorney in California. In 1965, she was appointed to the Arizona Senate, becoming the first woman to serve as the majority leader of a state senate. In 1975, she was appointed to the Arizona Court of Appeals, and then to the Arizona Supreme Court in 1979. Two years later, President Ronald Reagan nominated her to the United States Supreme Court.

During her time on the Supreme Court, Justice O'Connor was a strong advocate for women's rights. She authored several key opinions that advanced gender equality, including the 1996 decision in United States v. Virginia, which struck down the Virginia Military Institute's male-only admission policy. In this decision, Justice O'Connor wrote that gender-based classifications must be substantially related to an important governmental objective in order to be constitutional.

Justice O'Connor retired from the Supreme Court in 2006, citing the need to care for her husband who had been diagnosed with Alzheimer's disease. In retirement, she continued to advocate for civics education and the importance of an independent judiciary. She founded the O'Connor Judicial Selection Initiative, which aims to improve the process of selecting judges.

Justice O'Connor's appointment to the Supreme Court was a landmark moment in women's history. It demonstrated that women could serve in the highest positions of power in the United States and paved the way for future women in the legal profession. Her contributions to women's rights also helped to advance gender equality in the United States.