Americans are voting under the shadow of a resurging COVID-19 pandemic, with an alarming increase in cases nationwide and the number of people hospitalised reaching record highs in a growing number of states.
While daily infections are rising in all but three states, the surge is most pronounced in the midwest and southwest.
Missouri, Oklahoma, Iowa, Indiana, Nebraska, North Dakota and New Mexico have all reported record high hospitalisations this week.
Nebraska's largest hospitals started limiting elective surgeries and looked to bring in nurses from other states to cope with the surge.
Hospital officials in Iowa and Missouri warned bed capacity could soon be overwhelmed.
The resurgence looms over candidates and voters, fearful of both the virus itself and the economic toll of any new shutdowns to control its spread.
While many Americans took advantage of expanded access to mail-in voting, lines were long in many polling places on Tuesday, with record turnout expected and reminders of the pandemic everywhere.
"It's very serious that we have 400 people gathered in one space at the height of the pandemic here in Wisconsin," said Claire Woodall-Vogg, election commission director of Milwaukee.
"We've tried to take every measure to limit the movement throughout the room."
Wisconsin health officials reported 5771 new coronavirus cases Tuesday, a new record.
In Indiana, the Republican candidate for attorney general tested positive for COVID-19.
Hand sanitizer on voters' hands caused a ballot scanner to jam at a polling place in Des Moines, Iowa, secretary of state spokesman Kevin Hall said.
Meanwhile, Iowa hospital officials warned facilities and staff could be overwhelmed without serious efforts to curtail the virus spread.
The seven-day rolling average of the state's positivity rate reached 36.4 per cent over the weekend, the third-highest in the nation behind South Dakota and Wyoming. Hospitalisations reached a record 730 on Monday.
Health officials in Nebraska said hospitalisations have doubled in recent weeks, reaching a record 613 on Sunday.
"No doubt if this trend continues - not just at our hospitals - but every hospital in the state could be at capacity in a very short period of time," said Dr Cary Ward, chief medical officer for CHI Health's network of 14 hospitals across Nebraska and Iowa.
Missouri reported 1659 hospitalisations statewide on Monday, surpassing by 10 the previous record set a day earlier.
Among the five additional deaths was a 13-year-old boy, the first child under 14 to die from the virus in Missouri.
New Mexico's hospitalisations marked a new high for the 12th consecutive day, with 401 on Tuesday. It also set a record for the number of daily cases, 1141.
In Colorado, officials said more residents have been hospitalised than at any time since April.
The virus has killed more than 232,000 people in the country and total confirmed cases have surpassed 9 million.