Lisa LaTrelle Blunt Rochester (née Blunt; born February 10, 1962) is an American politician serving since 2025 as the junior United States senator from Delaware. From 2017 to 2025, she served as the U.S. representative for Delaware's at-large congressional district. A member of the Democratic Party, she is the first woman and first African American to represent Delaware in both chambers of Congress.

Blunt Rochester began her political career working for Tom Carper, first in the House of Representatives, and later as he became governor of Delaware. She was appointed deputy secretary of Delaware's Department of Health and Social Services in 1993 and secretary of the Department of Labor in 1998. Blunt Rochester was first elected to the U.S. House of Representatives in 2016. During the 2020 presidential election, she was one of Joe Biden's campaign co-chairs.

In 2023, Blunt Rochester announced her candidacy to represent Delaware in the United States Senate in the 2024 election and succeed the retiring Carper, who endorsed her in the race. She won the Democratic primary unopposed and defeated Republican nominee Eric Hansen by a landslide in the general election.

Blunt Rochester was born in Philadelphia, Pennsylvania, on February 10, 1962. Her family moved to Wilmington, Delaware, in 1969. Her father, Ted Blunt, was an educator who served on the Wilmington City Council, including as council president. Her mother, Alice LaTrelle, worked in retail. Her sister Marla Blunt Carter is a professor at Rutgers University.

Blunt Rochester attended Padua Academy, began college at Villanova University and transferred to the University of Delaware in her sophomore year. She left college to live in Europe, and later received her Bachelor of Arts in international relations from Fairleigh Dickinson University and her Master of Arts in urban affairs and public policy from the University of Delaware.

Blunt Rochester worked for Tom Carper as an intern in 1989, when he represented Delaware's at-large congressional district in the United States House of Representatives. After the internship, she continued to work for Carper as a constituent relations caseworker, and worked on his transition team when he was elected governor of Delaware. Carper appointed her deputy secretary of the Department of Health and Social Services in 1993 and secretary of the Department of Labor in 1998. Governor Ruth Ann Minner named Blunt Rochester the state personnel director in 2001.

In 2004, Blunt Rochester left government service and became the CEO of the Metropolitan Wilmington Urban League.

Blunt Rochester ran for the United States House of Representatives in Delaware's at-large congressional district in the 2016 election. She won the Democratic Party nomination on September 13 with 44% of the vote in a five-candidate primary, defeating State Senator Bryan Townsend and venture capital firm owner Sean Barney. In the November 8 general election, she defeated the Republican nominee, Wyoming Mayor Hans Reigle. When she was sworn into office on January 3, 2017, she became the first woman and the first African-American to represent Delaware in Congress. During her swearing-in, she carried a scarf imprinted with her great-great-great-grandfather's Reconstruction Era voter registration card. He had been a slave.