Katherine Moore Porter (born January 3, 1974) is an American politician, law professor, and lawyer who is the U.S. representative from California's 47th congressional district since 2023, previously representing the 45th congressional district from 2019 to 2023. She is the first Democrat to be elected to represent the 45th district, covering much of south-central Orange County, including Irvine, Tustin, and Lake Forest along with large portions of Anaheim and Laguna Niguel. Porter was reelected in 2022 in the newly redistricted 47th congressional district.