Irene might have been downgraded to a tropical storm before reaching Connecticut, but the massive storm caused serious damage across the state.
More than 750,000 people were without power at the height of the storm on Sunday and almost 700,000 still had no power on Monday.
Power crews were unable to assess the scope of the damage, or determine how long it would take to repair, Gov. Dannel Malloy said.
At least 2,000 utility poles have been damaged in the storm and an unknown number of electrical wires were brought down.
United Illuminating was forced to take a substation on Congress Street in Bridgeport offline after it became flooded and much of Bridgeport was without power because of that. As of Monday morning, 12 percent of the state's largest city still had no electricity.
Structural damage was being reported to homes from East Haven to Milford and Fairfield.
In Fairfield, the water from Long Island Sound had surged a half mile inland, trapping some people in their homes, according to Fairfield police.
Homeowners in East Haven were also trapped by flood waters, according to East Haven Mayor April Capone.
Malloy surveyed damage in East Haven and West Haven.
Connecticut also had two deaths related to Hurricane Irene. One person died in a house fire in Prospect caused by downed wires, Malloy said. Two firefighters received electrical shocks while fighting that fire and were hospitalized, but were expected to be okay, Malloy said.
One person died in the rushing flood waters Sunday when he was swept away after his canoe capsized while on a flooded Route 72 in Bristol.
As the cleanup from Irene begins, lives are far from getting back to normal. Dozens of schools canceled the first day of classes, which were scheduled for Monday.
Damage to catenary wires above the Metro North tracks has kept the MTA from restarting service on the New Haven Line.
Malloy urged anyone who regularly relies on Metro North for their commute to find alternate transportation until further notice.