1999: Writes the majority ruling opinion in the 5-4 sexual harassment ruling that public school districts that receive federal funds can be held liable when they are "deliberately indifferent" to the harassment of one student by another. Aurelia Davis v. Monroe County Bd. of Ed
December 2000: Votes in the majority to end the recount in Florida which leads to George W. Bush becoming president of the United States. O'Connor and Anthony M. Kennedy are the only justices who do not attach their names to either a concurring or dissenting opinion in the case. Bush v. Gore
2009: Founded the 501(c)3 non-profit organization, O'Connor House, dedicated to solving complex issues through civil discourse and collaborative action. In March 2015 O'Connor House, became the Sandra Day O'Connor Institute. O'Connor serves as Founder and Advisor to the O'Connor Institute.
2011: Becomes the Co-Chair of the National Advisory Board at the National Institute for Civil Discourse (NICD). The institute was created at the University of Arizona after the tragic shooting of former Congresswoman Gabrielle Giffords in 2011, that killed 6 people and wounded 13 others.
April 2013: The Board of Directors of Justice at Stake, a national judicial reform advocacy organization, announced that O'Connor would be joining the organization as Honorary Chair.
September 25, 2018: In recognition of the day Sandra Day O’Connor was sworn in as an Associate Justice to the Supreme Court of the United States and because she has distinguished herself as an extraordinary Arizonan and American who impacted our nation’s history for all future generations, Arizona Governor Doug Ducey declared September 25, 2018, as Sandra Day O'Connor Day.
October 23, 2018: Sandra Day O'Connor announced in a letter that she is in the early stages of what is likely Alzheimer's disease and is retiring from public life.
July 18, 2019: The O'Connor House was added to the National Register of Historic Places. O'Connor lived in the home from 1958 until 1981.
In the West in remote areas where what you see is this enormous heaven and what a small place mankind has in that space. But you hope that what you see also lets you exist and be yourself despite the small speck that you are in the overall scheme of things.
- Sandra Day O'Connor
On October 28, 2013, the National Portrait Gallery at the Smithsonian Institute in Washington, D.C. celebrated the arrival of Nelson Shanks’s The Four Justices, a tribute to the four female justices who have served on the U.S. Supreme Court. The work is monumental; it measures approximately seven feet by five-and-a-half feet. Only men had sat on the bench of the Supreme Court until President Ronald Reagan appointed Sandra Day O’Connor in 1981. After O’Connor, the next woman to receive an appointment was Ruth Bader Ginsburg, a nominee of President Bill Clinton in 1993. President Barack Obama appointed Justices Sonia Sotomayor and Elena Kagan. Shanks’s oil on canvas painting is on loan to the National Portrait Gallery from Ian and Annette Cumming.