September 21, 2012, 4:00 PM GMT+0

Democratic President Barack Obama holds a solid 18-point lead lead over Republican challenger Mitt Romney in California, 54% Obama to 36% Romney, in a poll of 1,456 registered voters statewide, conducted by YouGov.

In California:

Partisan loyalty is strong on both sides, as 94% of Democrats are sticking with Obama and 92% of Republicans are voting for Romney.

Independents split, 44% for Romney and 44% for Obama.

Women favor Obama by 2-to-1, 64%-32%, while men favor Obama by a narrower margin, 49%-45%.

Obama enjoys his widest leads in the San Francisco Bay area (68%-25%), in Los Angeles County (67%-28%) and in the Coastal region (53%-39%). Obama has a nominal lead in Southern California (49% Obama-47% Romney).

Romney only leads in one region, the Inland/Valley region (50% Romney-45% Obama).

The oldest voters age 65+ are split (49%-49%). The youngest under age 30 favor Obama (61%-29%), and Obama also scores well with voters age 30-44 (70%-24%).

Incumbent Democratic Senator Diane Feinstein leads, 52%-34%, over Republican Senate challenger Elizabeth Emken.

Voters in California are leaning decisively in favor of voting for Democratic candidates for the U.S. House, with 48% intending to vote for the Democratic candidate for the House in their district, and 35% for the Republican. The poll was conducted online September 7-14, 2012.

Sampling method: Respondents were selected from YouGov’s panel using sample matching. A random sample (stratified by age, gender, race, education, and region) was selected from the 2005–2007 American Community Study. Voter registration, turnout, religion, news interest, minor party identification, and non-placement on an ideology scale, were imputed from the 2008 Current Population Survey Registration and Voting supplement and the Pew Religion in American Life Survey. Matching respondents were selected from the YouGov panel, an opt-in Internet panel.

Weighting: The sample was weighted using propensity scores based on age, gender, race, education, news interest, voter registration, and non-placement on an ideology scale.

Number of respondents: 1,456 registered voters statewide.

Margin of error + 3.1% (adjusted for weighting).

Click here for a complete report of results