Authorities in Pennsylvania have ordered the evacuation of up to 200,000 people from an area around a rain-swollen river.
The evacuations were ordered Wednesday along the Susquehanna River and follow days of rain that drenched parts of the eastern United States.
The nation's capital, Washington, D.C., remains under a state of emergency. Some federal government buildings are closed because of water damage.
Outside Washington, more than 2,000 people were evacuated overnight in Montgomery County, Maryland, from an area surrounding a swollen lake.
Elsewhere in Maryland, three people were killed after they were swept away in rushing water. Two teenagers in Maryland also have been missing since Tuesday. They were last seen heading to a swollen creek.
Forecasters say up to 30 centimeters of rain had fallen on Washington since Friday. Sunny skies were over the city Wednesday.
Flooding also occurred in the states of New Jersey and New York. A state of emergency has been declared in 10 New York counties.
Some information for this report was provided by AP and Reuters.