TALLAHASSEE | An estimated 180,000 non-U.S. residents are registered to vote in Florida, according to state records. It’s a tightly held secret not shared with county election officials or the state’s election chief even after he took the job.

The large number of non-residents potentially on state voter rolls was first identified in early 2011, when the Department of Highway Safety and Motor Vehicles turned over residency information to the Department of State.

Using a 1.4 million voter sample, the state estimated at the time that there were “almost 900,000 voters that may or may not be U.S. citizens” in Florida according to documents obtained by the Times-Union. Verification of citizenship has whittled that number to the current 180,000.

The group, termed “immigrants,” is comprised of people who are in the United States legally on a permanent basis. A separate group of roughly 2,600 “non-immigrants” — people here legally on a temporary basis — also may be registered.

State estimates show 3,600 immigrant voters in Duval County. That number is “less than 500” in Clay County, said Clay County Supervisor of Election Chris Chambliss.

So, how did so many non-residents register to vote?

“From my understanding, it can happen when people go to get driver’s license,” said Duval Supervisor of Elections Jerry Holland.

Courtney Heidelberg, a Motor Vehicles spokeswoman, said if a person is not a resident, there should be no option to register.

“A possible explanation would be they could have registered prior to when the department began to collect citizenship information and haven’t renewed or visited us since then,” she said.