Factbox: Five House races still undecided

WASHINGTON (Reuters) - Nearly three weeks after Republicans swept Democrats from power in the U.S. House of Representatives, five House races remain undecided and the winners might not be clear for days -- or longer.

Democrats lead in three of those races, but in several contests the final results may await recounts or court rulings. Republicans gained at least 61 House seats in the election and will have a majority when the new Congress convenes in January.

Here is a look at the undecided House races:

California's 11th District

Democratic incumbent Jerry McNerney declared victory but Republican challenger David Harmer has refused to concede as election officials count the final ballots in a race that McNerney leads by about 1,700 votes.

California 20th District

Democratic incumbent Jim Costa has expanded his lead over Republican Andy Vidak to about 2,700 votes as officials count the remaining absentee and provisional ballots. A final count could be completed this week.

Texas 27th District

Democrat Solomon Ortiz, a 14-term House veteran, still trails Republican challenger Blake Farenthold with a manual recount of their south Texas race nearly completed. Farenthold leads by about 800 votes.

New York 1st District

In a near dead heat, Democratic incumbent Tim Bishop has inched ahead of Republican challenger Randy Altschuler by about a dozen votes as absentee ballots are counted. About 1,200 absentee ballots have been challenged, and the courts may decide the winner.

New York 25th District

Republican Ann Marie Buerkle leads Democratic incumbent Dan Maffei by about 560 votes with a court hearing scheduled for Tuesday on challenged ballots. Maffei has reserved his right to ask for a manual recount.

(Reporting by John Whitesides in Washington; Editing by Vicki Allen)