The heatwave that gripped much of the United States over the 250th Independence Day weekend killed more than two dozen people across the East Coast, Southeast and Southwest.

In New Jersey, at least 29 people died from the heat across 10 counties, according to the state's Department of Health, most found in homes without air conditioning.

New Jersey Health Commissioner Raynard Washington confirmed at a news conference on Saturday that victims ranged in age from younger adults to elderly.

"Extreme heat is the number one weather-related killer in America, and this is the hottest stretch we've seen in over 14 years," New Jersey Governor Mikie Sherrill said at the same news conference.

The mercury topped 37.8 degrees Celsius in more than 20 states, with at least 148 daily heat records set between June 30 and July 5, according to the FOX Forecast Center.

In Chicago, four people died of heat-related causes, while in Mississippi, an 83-year-old woman died of heat exposure after falling in a garden near her house. New York City's hot streak sent hundreds of residents to emergency rooms.

Washington, DC, recorded its warmest July 4 on record at 39.4 degrees Celsius. The Great American State Fair, held on the National Mall as part of the 250th anniversary celebrations, was temporarily closed Friday after emergency crews treated 44 people, 11 of whom hospitalized, many for heat-related illnesses and injuries, NBC News reported. Several other events scheduled for Saturday, including an Independence Day parade, were also canceled.

Philadelphia recorded historic highs of at least 38.3 degrees Celsius for three days running for the first time since records began. Atlantic City tied its all-time highest temperature on Saturday, when the temperature reached 41.1 degrees Celsius.

(With input from Xinhua)