Eight congressional races remain undecided one week after election day, though Republicans appear set to add to their historic gains.

Seven races for the House are yet uncalled by the Associated Press, and Democrats were defending all seven. Of that group, only two Democrats lead their Republican opponents, with the average vote differential being fewer than 600 votes in each.

In California’s 11th district, two-term incumbent Democrat Jerry McNerney has a 624-vote lead over Republican David Harmer, with absentee and provisional ballots still being counted.