Dianne Emiel Feinstein (née Goldman; June 22, 1933 – September 29, 2023) was an American politician who served as a United States senator from California from 1992 until her death in 2023. A member of the Democratic Party, she served as mayor of San Francisco from 1978 to 1988.

A San Francisco native, Feinstein graduated from Stanford University in 1955. She was elected to the San Francisco Board of Supervisors in 1969 and immediately became the board's first female president upon her appointment in 1970. In 1978, during a third stint as the board's president, the assassinations of Mayor George Moscone and City Supervisor Harvey Milk drew national attention. Feinstein succeeded Moscone as mayor and became the first woman to serve in that position. During her tenure, she led the renovation of the city's cable car system and oversaw the 1984 Democratic National Convention. Despite a recall attempt in 1983, Feinstein was a popular mayor and was named the most effective mayor in the country by City & State in 1987.

After losing a race for governor in 1990, Feinstein was elected to the U.S. Senate in a 1992 special election. In November 1992, she became California's first female U.S. senator; shortly afterward, she became the state's senior senator when Alan Cranston retired in January 1993. Feinstein was reelected five times. In the 2012 election, she received 7.86 million votes, the most popular votes received by any U.S. Senate candidate in history. Feinstein authored the 1994 Federal Assault Weapons Ban. She was the first woman to chair the Senate Rules Committee and the Senate Intelligence Committee and the first to preside over a U.S. presidential inauguration. Feinstein chaired the Senate Intelligence Committee from 2009 to 2015 and was the ranking member of the Senate Judiciary Committee from 2017 to 2021.