"We are working around the clock until that last customer is restored," spokesman Scott Surgeoner said.
First Energy also owns New Jersey Power Central Power & Light, which is trying to restore power to nearly 1 million customers, including about 91,500 in Warren and Hunterdon counties.
PPL and Met-Ed also are working to restore power to 29,000 customers in Berks County and 43,000 in Monroe County.
In addition, PPL has about 14,000 customers out in Schuylkill and Carbon counties.
In Southeastern Pennsylvania, Peco had 420,000 customers without power as of Wednesday. Of those, about 75 percent are in Montgomery and Bucks counties. Peco has declared it the worst power outage in its history after restoring to more than 430,000 customers since the storm began.
Bucks County is perhaps the hardest hit county in the state as far as the number of customers without power, which as of Wednesday totaled about 201,000 customers —173,000 Peco, 22,069 PPL and 6,015 Met-Ed.
Although downgraded to a post-tropical storm from a hurricane just before striking near Atlantic City about 8 p.m. Monday, Sandy left a huge swath of destruction as waterways swelled and surged along the coast. In Pennsylvania, including the Lehigh Valley region, the wind brought most of the destruction rather than the rain.
The National Weather Service shows 1.43 inches of rain fell at the Lehigh Valley International Airport near Allentown over the three-day storm, but a weather spotter measured a wind gust of 81 mph Monday night in South Allentown.
No major flooding issues were reported or expected in the aftermath of the storm, which as of Wednesday has been downgraded to a low pressure system as it continued moving north through western Pennsylvania Wednesday.
All of the weather warnings for Pennsylvaina expired with the storm's exodus toward New York.
Corbett is expected to inspect damage across the state by helicopter Wednesday, but on Tuesday he believed the damage would not be as severe as from last year's Hurricane Irene and Tropical Storm Lee.
In the Lehigh Valley region, the near hurricane-strength wind gusts felled trees and limbs fell into homes, across roads and on power lines and blew away roofs.
Parts of Easton's College Hill neighborhood re inaccessible because the trees that fell are two large for city crews to remove, Steckman said.
Allentown Fire Chief Robert Scheirer said widespread wind damage resulted in more than 60 calls Monday night from residents and business owners with lost or damaged roofs.
In the 600 block of Front Street, wind ripped a roof from an entire row of apartments, and the roof at the city's Mack South Fire Station in the 1900 block of Lehigh Street was also damaged in the storm, Scheirer said.
Few injuries were reported, but five city residents were hospitalized for carbon monoxide poisoning caused by a generator they were using inside their home, he said.
Local governments, schools and colleges remained shuttered, with Lehigh University canceling classes for the remainder of the week. Kutztown and DeSales universities and Cedar Crest, Moravian and Lafayette colleges said they will remain closed Wednesday. Muhlenberg College and Northampton County Community College, except for its Easton campus, reopened Wednesday. However, very few students showed up Wednesday.
Many area school districts, including Saucon Valley, Easton Area, Northampton Area, Nazareth Area and Bangor Area school districts canceled classes for a third day.
Major hospitals stayed open throughout the storm, but there was sporadic activity at outpatient and physician offices related to power outages. Hospital officials asked patients to check their web sites for updates on their satellite facilities.