The decision would give the Republican nominee one final shot at convincing voters in the vital battlegrounds to back his candidacy. Ohio is arguably the hardest-fought contest of the race, with both candidates visiting on Monday. Pennsylvania has voted Democrat in past presidential elections, but Romney is making a late play to expand the map.
Fox News is told the campaign plans to hit Cleveland and Pittsburgh on Tuesday.
Aides told Fox News they want to leave nothing on the table, no stone unturned in the search for last-minute, undecided votes.
The Obama campaign, meanwhile, has no plans to campaign on Tuesday. One top adviser said doing so can be perilous because it can tie up highways and divert resources -- rather than allow campaigns to focus on door-knocking and getting people to the polls.
Fox News' John Roberts, Carl Cameron and Ed Henry contributed to this report.