https://www.yahoo.com/news/puerto-ricos-migration-florida-could-turn-state-democratic-012255400.html

“Puerto Rico is a US territory. Though Puerto Ricans are US citizens with US passports, they can only vote in presidential primaries.

If they live on the island, they cannot vote in US presidential elections. If they are living on the mainland, they can register to vote including for president, in whichever state they live.

Of the five million Puerto Ricans living in the United States mainland according to US Census figures for 2015, one million reside in Florida.”