It might seem there is no more awesome power available to the government than a national emergency declaration like the one President Trump announced on Friday in response to the rapidly spreading coronavirus.

But the governors, county executives and mayors across the country who have declared states of emergency in their own areas have actually unlocked even more sweeping powers, according to legal experts.

While those powers vary by jurisdiction, they generally include the ability to impose curfews, order people and traffic off the street, mandate quarantines, ration goods, declare price controls, suspend alcohol consumption and limit public gatherings, according to Elizabeth Goitein, a director of the liberty and national security program at the New York University School of Law’s Brennan Center for Justice.

“The state and local governments have extraordinarily broad powers to handle public health crises — much broader than the federal government has,” Ms. Goitein said. “The federal government has more money, but state and local officials have police powers, essentially their authority to maintain public health and safety.”