Residents were advised to postpone or cancel gatherings of more than 250 people, including sports events, conferences and concerts, through at least the end of March. The order required local governments not to permit them.

“I have the ability as governor to enforce this,” he told reporters who, in accordance with social distancing guidelines, were spaced out in a briefing room, “But I don’t think we’ll need to do that.”

[Here’s a glossary of terms you may need to know.]

State officials also advised against gatherings in smaller venues, such as auditoriums, that don’t allow for six feet of distance between people.

Groups of high-risk people, such as those in retirement or assisted-living facilities, should be limited to no more than 10 people, officials said.

Mr. Newsom said that Disneyland and casinos were exempted from the restrictions for the time being, since they posed uniquely complicated challenges that require more conversations.

He said that the order applied to non-essential gatherings — places like schools and courthouses were also exempt, but subject to more specific guidance.

“Changing our actions for a short period of time will save the life of one or more people you know,” Mr. Newsom said in a statement. “That’s the choice before us.”

President Trump suspended most travel from Europe for 30 days starting on Friday. [The New York Times]

Walmart, Uber and other companies adjusted their sick-leave policies as the coronavirus spreads. [The New York Times]

If you missed it, here’s why big employers have a financial incentive to give paid sick leave. [The New York Times]

Also: The Times wants to hear about how the coronavirus outbreak has affected your college. Click here to submit a video or write to us.