The heat wave shattered temperature records, led to more emergency room visits, and created serious risks for millions of people preparing to spend the Fourth of July outdoors, Anadolu Agency reported.
More than a dozen places in the Mid-Atlantic and Northeast either matched or broke their record high temperatures for Friday, including Washington, DC.
The city reached 39C (102F), exceeding the previous record of 38C (101F) set in 1872.
By Saturday, the worst of the heat is expected to move slightly south, though Washington, DC, is still forecast to reach 39C (102F).
That would make it the hottest Fourth of July ever recorded in the city.
Philadelphia and New York City are also expected to approach 38C (100F), with heat index values near 41C (105F).
Several holiday events were canceled or postponed because of the extreme heat.
MNA