WASHINGTON, Oct 13 (Reuters) - Republicans are headed for big gains in the U.S. Senate in the Nov. 2 election and are threatening to take a majority, according to poll averages compiled by the website Real Clear Politics.
Republicans must sweep nearly all the competitive races to pick up the 10 seats needed for control in the Senate, where Democrats now hold a 59-41 edge.
The poll averages show Republicans leading in races that would give them a net gain of seven seats, which would leave Democrats with a 52-48 edge.
Two states moved back into the Democratic column on Wednesday. Democratic Senator Patty Murray reclaimed the lead in Washington, moving ahead of Republican Dino Rossi by 2.7 percentage points.
In Nevada, Democratic Senate leader Harry Reid regained a lead over Republican Sharron Angle by less than 1 percentage point.
In the House of Representatives, the Real Clear Politics averages show Republicans with a growing edge. Republicans lead with 211 seats to 185 for Democrats, with 39 contests considered toss-ups in the battle for a 218-seat majority.
Republicans must pick up 39 Democratic seats to claim House control in November.
Here is a look at the Real Clear Politics poll averages in the most competitive Senate races, with the party currently holding the seat in parenthesis.
* California (Democrat) - Democratic Senator Barbara Boxer leads Republican Carly Fiorina by 3.7 percentage points.
* Colorado (Democrat) - Republican Ken Buck leads Democratic Senator Michael Bennet by 3 percentage points.
* Connecticut (Democrat) - Democrat Richard Blumenthal leads Republican Linda McMahon by 8.7 percentage points.
* Delaware (Democrat) - Democrat Chris Coons leads Republican Christine O‘Donnell by 17.2 percentage points.
* Florida (Republican) - Republican Marco Rubio leads independent Charlie Crist by 16.2 percentage points, with Democrat Kendrick Meek trailing.
* Illinois (Democrat) - Democrat Alexi Giannoulias leads Republican Mark Kirk by less than 1 percentage point.
* Kentucky (Republican) - Republican Rand Paul leads Democrat Jack Conway by 5.3 percentage points.
* Missouri (Republican) - Republican Roy Blunt leads Democrat Robin Carnahan by 9.4 percentage points.
* Nevada (Democrat) - Democratic Senate Leader Harry Reid leads Republican Sharron Angle by less than 1 percentage point.
* New Hampshire (Republican) - Republican Kelly Ayotte leads Democrat Paul Hodes by 9 percentage points.
* Ohio (Republican) - Republican Rob Portman leads Democrat Lee Fisher by 15 percentage points.
* Pennsylvania (Democrat) - Republican Pat Toomey leads Democrat Joe Sestak by 7.5 percentage points.
* Washington (Democrat) - Democratic Senator Patty Murray leads Republican Dino Rossi by 2.7 percentage points.
* Wisconsin (Democrat) - Republican Ron Johnson leads Democratic Senator Russ Feingold by 6.7 percentage points.
Republicans also hold commanding leads in three Democratic-held states -- Arkansas, Indiana and North Dakota. (Compiled by John Whitesides; Editing by Doina Chiacu)