Mia Costello
Mia C. Costello is a Republican politician from Alaska. She is a member of the Alaska House of Representatives from the 15th district. She previously represented the 20th district from 2011 to 2015 and served as a member of the Alaska Senate, representing District K from 2015 to 2023.
In November 2010, Costello defeated Democratic incumbent Bob Buch to win her House seat. Costello received 3,696 votes to Buch's 2,873. Costello served on the House Finance Committee and as chair of the Natural Resources Finance Subcommittee. She ran for the Senate seat vacated by Democrat Hollis French in 2014, picking up the seat to add to the Republican Senate Majority.
Costello served as minority leader for the 2025 legislative session but resigned the position in November 2025.
Prior to being elected to the Alaska State House, Costello worked as a school teacher, legislative aide, and as deputy communications director for Governor Frank Murkowski.
After graduating from West High School, she earned her B.A. from Harvard University and later a Master of Art in Teaching from the University of Alaska Southeast.