Kathryn Kimball Mizelle (née Kathryn Anne Kimball; born 1987) is an American lawyer and jurist serving as a United States district judge of the United States District Court for the Middle District of Florida. At age 33, she was the youngest person chosen by President Donald Trump for a lifetime judicial appointment. Mizelle's nomination was confirmed by a Republican majority on the Senate after a party-line vote of 49–41 during a lame-duck session. On April 18, 2022, Mizelle struck down the CDC's federal COVID-19 mask mandate on airplanes and public transportation.