Heather R. Mizeur (/mɪˈzɪər/ mih-ZEER; born December 6, 1972) is an American politician who served as a member of the Maryland House of Delegates from January 10, 2007, to January 14, 2015, representing the 20th district in Montgomery County. She was a candidate for governor of Maryland in the 2014 election but lost the Democratic primary to Lieutenant Governor Anthony Brown. In 2021, she announced her intention to run for Maryland's 1st congressional district in the 2022 election against incumbent Republican congressman Andy Harris.Mizeur won the primary election on July 19, 2022, defeating R. David Harden by nearly 40 points to become the Democratic nominee in the November 8 general election. She lost the general election to Harris by 11 points.