Up to four million undocumented immigrants who have lived in the United States for at least five years can apply for a program that protects them from deportation and allows those with no criminal record to work legally in the country, President Obama is to announce on Thursday, according to people briefed on his plans.

An additional one million people will get protection from deportation through other parts of the president’s plan to overhaul the nation’s immigration enforcement system, including the expansion of an existing program for “Dreamers,” young immigrants who came to the United States as children. There will no longer be a limit on the age of the people who qualify, the New York Times reports.

But farm workers will not receive specific protection from deportation, nor will the Dreamers’ parents. And none of the five million immigrants over all who will be given new legal protections will get government subsidies for health care under the Affordable Care Act.

These new details about the broad reach of Mr. Obama’s planned executive action on immigration emerged as he prepared to speak to the nation in a prime-time address on Thursday night. On Friday, the president is to travel to Las Vegas to rally public support for his plan in a state where Hispanics are a growing and politically powerful constituency.