Soldiers have been airlifting storm-relief supplies to Vermont towns which remain cut off after the trail of destruction left by Irene.
More than 200 roads are blocked or washed away in Vermont, hampering rescue efforts to 13 towns.
Irene killed 44 people in 13 US states, according to the Associated Press, and caused billions of dollars' damage.
About half of the 6.7 million people on the east coast who lost power still have no electricity.
Vermont is reeling from its worst floods since 1927, and officials warned some rivers and creeks there had yet to crest.
'Irene whacked us'
National Guard troops flew in food, water and other emergency supplies to the rural, mountainous state on Tuesday.
They also brought in some provisions by road, using heavy-duty lorries.
Irene had been expected to bring the most havoc to coastal areas, but some of its worst destruction took place far inland.
Governor Peter Shumlin told MSNBC television: "We've got a long slog ahead. Irene really whacked us hard."
In the Vermont town of Rochester, one resident, Wendy Pratt, used a generator to post an update on Facebook to tell of the chaos.
"People have lost their homes, their belongings, businesses," Ms Pratt wrote.
"The cemetery was flooded and caskets were lost down the river. So many areas of complete devastation."
Newlyweds' narrow escape
In the Vermont town of Pittsfield, two newlyweds from New York City were stranded after rising floodwaters hit their honeymoon cottage.
Marc Leibowitz and Janina Stegmeyer said they just escaped in a car before a bridge collapsed on Sunday. Dozens of their wedding guests were airlifted out by helicopter on Tuesday.
Irene dumped 11in (30cm) of rain on Vermont.
In New Jersey, the Passaic River measured 13ft (4m) above flood stage on Tuesday, the highest level since 1903, police sergeant Alex Popov said.
Emergency teams working in the state's Paterson city have rescued nearly 600 people from flooded homes in recent days.
New Jersey Governor Chris Christie warned more flooding was likely over the next 48 hours.
"For members of these communities who have lost everything, relief cannot come soon enough for them," he said.
Meanwhile, dozens of people were rescued from mountain towns in New York state that were cut off by washed-out roads and bridges. The storm dropped 13in of rain on the state.
'$20bn economic toll'
Airlines said it would be days before the thousands of passengers stranded by Irene find their way home.
The Amtrak railway service was suspended on Tuesday between Philadelphia and New York because of flooding.
The total economic damage caused by the storm could reach $20bn (£12bn), Standard & Poor's senior economist Beth Ann Bovino told Reuters news agency.
Irene hit North Carolina on Saturday as a hurricane, before moving north over major east coast cities, and weakening to a tropical storm over New England.
Even though it dissipated as it reached eastern Canada, Irene still caused chaos there. Crews are trying to clean up debris and restore electricity to thousands of householders.
Hopes were fading of finding alive a motorist who was swept away on a flooded road in Yamaska, Quebec.
CBC reported, meanwhile, that an 81-year-old man who left his cabin in Quebec during the storm was found dead just over a mile away.
Five people also died in the Dominican Republic and Haiti as Irene blew through the Caribbean.