"Go to China if you want communism," the woman, wearing a Stars and Stripes T-shirt, shouted at them from her car. "This is a free country."
Colorado, which has had 420 coronavirus deaths, is under a stay-at-home order until April 26.
There have been widespread demonstrations against the lockdown as the jobless figure hit 22 million and restrictions were extended in most states.
Protests have also erupted in Brazil, Peru, Kenya, Paris, parts of Russia, India, Lebanon and Iraq, as more than half the global population remained under some form of enforced confinement.
With the International Monetary Fund forecasting the worst global recession in a century, António Guterres, the UN secretary-general, warned of a risk of increased social unrest and violence "that would greatly undermine our ability to fight the disease".
President Donald Trump appeared to praise the actions of the US protesters during his White House briefing yesterday.
"These are great people," he said. "They are picketing a little bit because they want to get back to work. They've got cabin fever. They want their lives back."
Democrat Jay Inslee, Washington state's Governor, called the messages from the Trump Administration "schizophrenic".
He added: "To have an American president encourage people to violate the law, I can't remember any time during my time in America where we have seen such a thing."
Trump, under pressure to rescue an economy in freefall, has been looking for a way to ease the restrictions. A number of governors say a shortage of tests, which health experts touted as the best way to get people back to work safely, is among the more significant hurdles.
The US is conducting two million tests each day, according to the Covid Tracking Project. Dr Anthony Fauci, the nation's top infectious diseases expert, said the nation needed to treble the pace of testing.
Trump said the administration was preparing to use the Defence Production Act to compel US facilities to increase production of test swabs by 20 million per month.
WHAT THE POLLS SAY
Despite the protests, polls show a majority of Americans are cautious about the lifting of restrictions.
AROUND THE WORLD
In Brazil, President Jair Bolsonaro addressed demonstrators in Brasília.
He is one of the few global leaders to have openly railed against lockdown measures to combat the virus, doggedly asserting that the economic risks of shutting down Brazil's economy outweigh the dangers posed by a disease he refers to as a "little cold".
The protest included calls for the armed forces to shut down Congress and the Supreme Court and to return to military rule.
Police struggling to enforce lockdown restrictions have come under attack in France, with clashes reported in the poorer regions of a dozen cities in the past week.
In the northern Paris suburb of Villeneuve-la-Garenne, violence erupted when a young motorcyclist was injured in a collision with an unmarked police car. About 50 youths threw stones and set off fireworks at police, who retaliated with tear gas. Clashes between disaffected youths and police also broke out in other Paris suburbs, as well as in Bordeaux and the port of Le Havre.
In Russia, at least 1000 people rallied against lockdown restrictions yesterday in Vladikavkaz, a regional capital in the North Caucasus.
Hundreds of locals packed the city's main square, demanding to see the governor.
