New York

Much of New York state was without power, including New York City. Mayor Michael Bloomberg said it was likely the blackout started in the Niagara Falls area and quickly spread. Across Manhattan, people poured out of skyscrapers and started trudging home on foot. Traffic lights were out, and subways and buses stopped. New York’s three major airports were without power.

New Jersey

More than 1 million customers in northern New Jersey were without power for several hours. Gov. James E. McGreevey declared a state of emergency, mobilizing 700 National Guardsmen and 300 extra state troopers. Train service was suspended for about four hours, as were flights in and out of Newark Liberty International Airport.

Ohio

Power went out across a wide stretch of northern Ohio, from Toledo through Cleveland to the state’s eastern edge. Airline flights were canceled and traffic lights went blank during rush-hour traffic. FirstEnergy Corp. estimated 880,000 customers were without power Thursday evening. As night fell, 1.5 million people in Cleveland faced a water crisis because there was no electricity to pump water from Lake Erie.

Michigan

Power was out from Detroit to the state capital in Lansing. Detroit Metropolitan Airport remained open, but Northwest Airlines, its largest carrier, stopped all departing flights. The outage closed the Detroit-Windsor Tunnel, which links the United States and Canada and is used by 27,000 vehicles daily.

Connecticut

Power flickered across Connecticut and some areas of the state lost electric service. Northeast Utilities said nearly 58,000 customers were without power. Fairfield County and Connecticut shoreline towns appeared to be the hardest-hit.

Pennsylvania

The northwestern corner of the state was without power. Power went out to much of Erie, Forest and Venango counties, according to emergency management officials.

Vermont

A handful of northern Vermont towns were hit briefly. Several Franklin County communities lost power for about an hour. Customers in Highgate and Swanton also lost power momentarily. Richard Thompson, administrator in Swanton, said the outage was brief and “no different than a winter storm or when a squirrel gets into a transmitter.”

Canada

Blackouts were reported in Toronto, in Ottawa in the province’s eastern region, Windsor in the west and North Bay in northern Ontario. The blackout had not spread as far as Thunder Bay in northwestern Ontario, suggesting power in the north was sporadic.