Puerto Rico is closing 283 schools this summer following a sharp drop in enrollment in the past year, officials said.
Since May, schools have lost 38,762 students as the US territory works to rebuild following a devastating hurricane last year, the education department said in a statement.
"Half of the existing schools are at 60% of their capacity," it said. The department said only 828 schools will reopen in August.
Education Secretary Julia Keleher said planning to close so many schools was a tough call.
"We know it's a difficult and painful process. For this reason, we've done it in the most sensible way taking in consideration all the elements that could impact the daily lives of some families and the school communities in general," Keleher said.
The new school year budget includes some repairs to schools.
"Our boys and girls deserve the best education that we are capable of giving them taking into account the fiscal reality of Puerto Rico," Keleher said.
Before Hurricane Maria hit Puerto Rico on September 20, there already was an unprecedented migration from the Caribbean island to the mainland United States -- at least in part because of the US commonwealth's financial crisis.
The hurricane left millions of Puerto Ricans without power or running water. Schools were closed and jobs lost. Puerto Ricans are American citizens and can move to the states without visas or other paperwork. And so, many did.
In 2016, there were about 2 million more Puerto Ricans living in the mainland United States than in the US territory.
Lyman Stone, an economist working with Puerto Rico to develop population projections, said his early analysis of airline data from the US Department of Transportation shows 179,000 net airline travelers left Puerto Rico for the US between September and November.
Stone estimates the island's population will continue to shrink. If the island rebounds relatively quickly from Hurricane Maria, then the population will stay closer to 3 million in the next decade. If problems on the island snowball, pushing more people out, Stone estimates Puerto Rico's population could plunge below 2 million by 2040.