One Senate seat is up for election in Maine, held by a independent incumbent who caucuses with Democrats. Voters will also choose representatives for two House seats, one of which is held by a Democrat and one by a Republican. And they will select a governor, an office currently held by a Republican.
Maine’s House races use ranked-choice voting, meaning voters can list multiple candidates in order of preference instead of choosing a single one. If no candidate receives 50 percent of the “first-choice” vote, the bottom candidate is eliminated and their votes distributed based on voters’ second preference. See Maine’s primary results