The Romney campaign is arguing that the state, which has long backed Democrats in presidential contests, might be up for grabs. No Republican candidate, though, has carried Pennsylvania since 1988.
Additionally, a number of outside groups, led by Restore Our Future, at $2.1 million, and American Crossroads with $1.2 million, are launching ad buys in the Keystone State.
But with 91 percent of voters saying they were certain about their choice for president, Romney might have limited room to overtake Obama.
In the Franklin & Marshall poll, Romney has seen gains in his favorability. In September, only 34 percent of registered voters viewed him favorably, a figure that rose to 43 percent in the latest poll.
Romney also holds the edge on the economy, with 47 percent saying he would be best prepared to manage the recovery and 42 percent picking Obama. In September, Obama led on the economy by 47 to 43 percent.
Obama scores higher on foreign policy, with 56 percent preferring the president on the issue to 37 percent for Romney. Fifty-one percent said Obama would better handle the job of commander in chief to 42 percent for Romney.
The poll was conducted from Oct. 23 to 28 and has a 4-point margin of error.