|The US midterm elections are widely seen as a referendum on the Obama presidency [AFP]
WEST VIRGINIA - Democratic candidate Joe Manchin won the Senate race beating a late increase by Republican rival John Raese.
FLORIDA - Republican Marco Rubio, backed by the Tea Party movement, won the Senate race, beating Governor Charlie Crist, who ran as an independent.
Rubio, a Cuban American and former state politician, won the Republican primary over Crist because he was considered "more conservative".
KENTUCKY - Republican Rand Paul, a Tea Party favourite, won a Senate seat over Democrat Jack Conway.
The victory preserved a Republican Senate seat that Democrats had hoped to grab.
INDIANA - Republican Dan Coats won the Senate race over Democrat Brad Ellsworth. The victory by Coats, who retired previously from the Senate and had been working as a lobbyist, helped Republicans narrow the gap in the Senate.
WISCONSIN - Three-term Senator Russ Feingold lost his re-election bid in the Midwest states to Republican Ron Johnson, adding another seat to Republican gains in the chamber.
Feingold, one of the most liberal members of the Senate, had trailed in the polls for much the race.
ILLINOIS - Republican Mark Kirk won the seat formerly held by president Obama in the Senate.
The loss by the Democratic treasurer Alexi Giannoulias is seen as an embarrassment to Obama and his party in a state that typically leans Democratic.
The president campaigned there in the final days of the race.
PENNSYLVANIA - Republican Pat Toomey won a Senate race over Democrat Joe Sestak.
Toomey had the backing of the Tea Party movement and led for much of the race and hit Sestak hard over the struggling economy in a state that was once dominated by industrial manufacturers.
CALIFORNIA - Democratic Senator Barbara Boxer, one of the more powerful liberals in the Senate, won re-election.
NORTH DAKOTA - Republicans captured another Democratic Senate seat, Governor John Hoeven beating Democrat Tracy Potter in the race to replace retiring Democratic Senator Byron Dorgan.
ARKANSAS - Republicans picked up a key Senate seat with John Boozman defeating incumbent Democratic Senator Blanche Lincoln.
Lincoln had been considered one of the most vulnerable Democratic senators in the race because of her
support for Obama's healthcare policies.
CONNECTICUT - Attorney General Richard Blumenthal won the state's Senate seat over Republican Linda McMahon.
The close race was aimed at replacing retiring Democratic Senator Christopher Dodd.
MISSOURI - Democratic Representative Ike Skelton, chairman of the House Armed Services Committee, lost his re-election bid to Republican Vicky Hartzler, a former state politician who criticised Skelton for his support of legislation Democrats pushed through to try to control climate change.