Thirty-year Republican incumbent Senator Susan Collins lost her Maine Senate seat to Democratic challenger Troy Jackson

Federal and state elections held midway through a presidential term that determine control of Congress and shape the political direction of the country.

Maine's 2026 U.S. Senate election pits Republican Susan Collins against Democratic former state Senate president Troy Jackson on November 3, 2026, for a sixth term. Senate control could hinge on the outcome, while abortion-rights groups have targeted Collins's 2018 vote confirming Justice Brett Kavanaugh.