Estimated Pennsylvania vote Strongest for Clinton Strongest for Trump Erie Meadville Scranton Williamsport Wilkes-Barre Sharon New Castle State College Allentown Altoona Pittsburgh Johnstown Reading Harrisburg Lancaster Philadelphia York Erie Meadville Scranton Williamsport Wilkes-Barre Sharon New Castle State College Allentown Altoona Pittsburgh Johnstown Reading Harrisburg Lancaster Philadelphia York Erie Meadville Scranton Williamsport Wilkes-Barre Sharon New Castle State College Allentown Altoona Pittsburgh Johnstown Reading Harrisburg Lancaster York Philadelphia Erie Scranton Williamsport State College Allentown Pittsburgh Altoona Harrisburg Johnstown Philadelphia NYT Upshot/

Siena College poll Clinton 46% Trump 39%

If Donald J. Trump has a path to the presidency with big gains among white working-class voters, it has to run through Pennsylvania — a disproportionately white, blue-collar state with few Hispanic voters.

But a New York Times Upshot/Siena College poll released Thursday indicates that Pennsylvania remains out of reach for Mr. Trump.

Hillary Clinton leads him by seven percentage points, 46 percent to 39 percent, in a four-way race. And in a contest that could decide control of the Senate, the Republican senator Pat Toomey trails the Democratic challenger Katie McGinty by three points.

Hillary Clinton leads by a larger margin than Katie McGinty does in her Senate race against Pat Toomey.

A late push to win Pennsylvania has become a quadrennial and frustrating feature for Republicans in American presidential elections. The Democrats have won Pennsylvania in six straight presidential elections, but sometimes by only slim margins. The state has become even more important to Republican chances now that once-Republican states like Virginia and Colorado have slid into the Democratic column.

The state is full of old industrial cities like Scranton and Johnstown where Mr. Trump’s message on trade would seem to play well. And the turnout among white voters slipped in those areas in 2012, leading many to speculate that disaffected voters would respond to a conservative populist.

Mr. Trump’s message does seem to be playing well among the white working-class voters that Republicans have coveted for a decade. Over all, he leads among white voters without a college degree by a 17-point margin, 51 percent to 34 percent.

Pennsylvania has a large educational split. Below, the divide among whites.

It’s better than Mitt Romney’s 12-point victory with that group in the state in 2012, according to Upshot estimates. Mr. Trump appears to be especially strong in northeastern Pennsylvania, including the Scranton and Wilkes-Barre area, where Mr. Trump leads by 16 points. Mr. Romney won the region by four points in 2012.

But these gains would not be sufficient for Mr. Trump to win the state, even if he matched Mr. Romney’s standing among other voters — something he is not pulling off.

Mr. Trump has the support of just 76 percent of Republican voters and trails among white voters with a college degree by nine points, 47 percent to 38 percent. He has nearly no support among black and other nonwhite voters.

White voters Mrs. Clinton leads among white voters in the Philadelphia area, but might underperform in the northeast. Black voters Mr. Trump had the support of one black respondent to the survey.

Mr. Trump has claimed in recent weeks that the election might be rigged because of fraudulent voting in Philadelphia. There is no evidence to support his assertion, but the poll suggests that the Democrats will again pull off a huge victory in the city. Mrs. Clinton has a 77-9 lead in Philadelphia, putting her on track to approach or exceed President Obama’s 85-14 percent margin from 2012.

Mrs. Clinton’s 90-1 lead among black voters suggests she could win a unanimous share of the vote in some precincts in west and north Philadelphia. No black respondent from Philadelphia supported Mr. Trump in the survey.

The Senate race, though, looks more like a traditional Pennsylvania contest. Mr. Toomey has the support of 85 percent of self-identified Republicans. He is doing better than Mr. Trump in the Philadelphia suburbs, but not as well as Mr. Trump in traditionally Democratic parts of northeastern Pennsylvania.

Mr. Trump and Mr. Toomey do have one thing going for them: strength among voters who have a reliable track record of voting. According to our estimates, the two both lead among the category of voters deemed likeliest to vote. Mr. Trump’s lead among the likeliest voters might help him avoid a larger loss, but it also suggests that he won’t be able to count on a pool of missing white voters he hoped to lure to the polls.

Over all, Mrs. Clinton has a nine-point lead among registered voters, even larger than her seven-point edge among likely voters.

Support in a two-way race among voters who are...

The chart below is identical to the one above, except that the groups are scaled according to their share of the likely electorate.

Scaled to size of the electorate (two-way race)

The good news for Mrs. Clinton is that her supporters were just as likely as Mr. Trump’s supporters to say they would turn out to vote, despite their weaker track record of voting. If they do make it to the voting booth, Mrs. Clinton could post an even larger victory.

Mrs. Clinton has an 18-point lead among voters who did not participate in the 2012 election, according to our estimates, which are based on a combination of the poll results and voter file data. She fares even better among white voters who didn’t vote in 2012 than she does among white voters who did. It’s a pattern that has been true across all of the Upshot/Siena surveys in Florida, North Carolina and Pennsylvania.

There has not been an influx of new voters who might help Mr. Trump. According to our estimates, Mrs. Clinton has a 16-point lead among newly registered voters. That’s in no small part because Democrats have a 10-point registration edge among voters who have registered this year, but it’s also because those registering are disproportionately young and urban.

Even in a state that is disproportionately older and white, the demographic shifts are still helping the Democrats.

Where this poll fits in with other polls of Pennsylvania voters