The Republicans have gained control of the US House of Representatives, while cutting back on the size of the Democratic majority in the Senate to a handful of Senators.

On the latest numbers, Republicans hold 239 House seats to 185 for the Democrats, with 11 seats yet to be decided. The Republicans have already gained 60 seats, ignoring the 11 yet to be decided. The Republicans won more seats than in the decisive 1994 election, and have the largest Republican majority since the 80th Congress of 1947-49.

In the Senate, Democrats currently hold 50 seats, the Republicans 46, two independents caucus with the Democrats, and the result is too close to call in two others. Overall, the Senate will have a split of either 53-47 to the Democrats, or 52-48.

In the state of Washington, three-term Democratic Senator Patty Murray is leading by 13,000 votes in a race where most votes are cast by mail and many votes are yet to be received. In Alaska, 41% of votes counted have been cast as write-in votes, with 34% for the Republican and 24% for the Democrat. Those write-in votes will be examined to see who they voted for, and if at least 34% of voters voted for sitting Senator Lisa Murkowski, and have managed to cast a valid vote for her, she will win.

Democrats managed to hold on in several states where they were considered to be in trouble, including West Virginia, California, Colorado and Nevada. Democratic leader Harry Reid was considered particularly vulnerable in Nevada, but he managed to hold on by a comfortable 5.6% margin.

A majority of US state governors are now Republicans. On the current figures, the Republicans hold 29 state governorships, with 15 Democrats, one independent, and five undecided. Republicans gained a large number of Democratic governorships, including in most states in the centre of the US, such as Wyoming, New Mexico, Kansas, Oklahoma, Iowa, Wisconsin and Michigan.

In California, Democratic candidate Jerry Brown has returned to office after 28 years. He last served from 1975 to 1983, and managed to defeat former eBay CEO Meg Whitman, who spent more than $160 million on the race, including $143 million of her own money. Republicans also lost the governorship in Rhode Island to former Republican Senator Lincoln Chafee, who ran as an independent. The Democrats also gained the governorship in Hawaii, and are locked in tight contests for Republican governorships in Connecticut, Vermont and Minnesota.

In the House, more conservative members of the Democratic Party were hit particularly hard. Out of 54 members of the conservative Blue Dog Coalition, 22 members were defeated, and six retiring members’ seats were lost to Republicans. Three remain undecided, with only 23 out of 54 members returned. The moderate New Democrat grouping has also been hit hard. In contrast, the House Progressive caucus only lost three members to Republicans and one to retirement out of a 72-member caucus. This suggests a more polarised House, with fewer Democrats willing to work with John Boehner’s new Republican majority.

Republican gains in state legislatures and among governors will put them in a strong position when drawing new electoral boundaries before the 2012 election. These partisan gerrymandering efforts will be hampered by referendum results in California and Florida, the first and third largest states in the US. Floridians voted in favour of two amendments requiring the legislature to follow strict rules to draw fair boundaries, which managed to achieve the 60% threshold required for passage. More than 60% of Californians voted for a measure to expand the power of an independent redistricting commission to cover federal districts, and voted against a measure to abolish that commission by a similar margin.