Democrat Mary Peltola holds a razor-thin lead over Republican Senator Dan Sullivan in Alaska's US Senate race, but the contest remains uncalled, with tens of thousands of ballots still to count.

With about 76.8% counted, Peltola led 48.2% to 47.9% — a margin of just over 600 votes, per the Associated Press tally on Friday. Decision Desk HQ put the gap at 637 votes: Peltola 102,962, Sullivan 102,325.

Alaska is one of only two Senate races still uncalled after Tuesday's midterms, alongside Mississippi, where Democrat Scott Colom leads Republican Cindy Hyde-Smith by a similarly narrow margin.

Ranked-choice count set for 18 November

Neither candidate has passed 50% of first-choice votes, so under Alaska's ranked-choice system the winner will be decided by counting voters' second and later preferences once all ballots are in. Officials have scheduled the tabulation for Wednesday, 18 November.

An analysis by Alaska News of the state's ballot-level data found the race close to a tie once backup choices were counted: Sullivan would come out about 330 votes ahead after the two lower-placed candidates were eliminated. The analysis stressed this was not a final result.

Election officials still have to count early votes cast from 30 October, plus more absentee and questioned ballots; domestic absentee ballots can arrive until 13 November and overseas ballots until 18 November. The next updates are 10 and 13 November.

A wait of weeks, not days

Peltola acknowledged the long wait at her election-night rally. "It won't be hours, it won't be days, it will be weeks," she told supporters.

The race matters for the size of the Democrats' new Senate majority. Sullivan's campaign said its simulation put him ahead by 328 votes after transfers, while Peltola would finish ahead if she won just over half of the remaining votes.