Nine states reported record one-day increases in cases on Wednesday: Colorado, Idaho, Indiana, Maine, Michigan, Minnesota, Rhode Island, Washington and Wisconsin.
The pandemic has affected nearly every aspect of American life, including a record number of voters mailing in their ballots in Tuesday's presidential election, whose outcome has yet to be decided.
In addition to rising cases, on Tuesday hospitalizations topped 50,000 for the first time in three months. North Dakota reported only six free intensive care unit beds in the entire state on Wednesday, when it was one of 14 states that reported record levels of hospitalized COVID-19 patients.
Hospitalization are a key metric because they are not impacted by the amount of testing done.
The proportion of tests coming back positive is greater than 50% in South Dakota and over 40% in Iowa and Wyoming. The World Health Organization says rates of more than 5% are concerning because they indicate undetected community transmission.
Coronavirus deaths are trending higher but not at the same rate as cases. The United States is averaging 850 deaths a day, up from 700 a month ago.
The outbreak is hitting the Midwest the hardest, based on new cases per capita in recent weeks.
Illinois has reported 48,579 cases in the last seven days, more than any other state. Texas, which has twice as many residents, reported 47,932 cases and both California and Florida reported about 30,000 new cases each.
The previous US record for new cases in a day was 100,233 on Oct. 30, the highest ever reported by any country in the world.