The U.S. immigration crisis isn’t a land-locked problem. So many migrants are arriving in Florida by boat that a national park had to shut down so authorities could help all of the people.

According to the Sheriff’s Office in Monroe County, Florida, at least 500 migrants have arrived in small boats along the Florida Keys over the last several days. 300 migrants made landfall in the sparsely populated Dry Tortugas National Park.

“Like elsewhere in the Florida Keys, the park has recently seen an increase in people arriving by boat from Cuba and landing on the islands of Dry Tortugas National Park,” the National Park Service said in a release.

The park was closed down so law enforcement and medical professionals could evaluate the group of migrants. The group will eventually be moved to Key West. The Dry Tortugas National Park is expected to remain closed for at least a couple of days.

In a news release, which was also posted to social media, Sheriff Rick Ramsay said dealing with the influx of refugee arrivals is straining his department’s resources. The sheriff said he asked for federal assistance on Monday, but was told it would have to wait until the following day.

Sheriff Ramsay said the response “shows a lack of a working plan by the federal government to deal with a mass migration issue that was foreseeable.”

In addition to the landing at the national park over the weekend, 160 other migrants arrived in the Middle and Upper Keys. U.S. Customs and Border Protection said at least 88 of those migrants were from Cuba.

The number of migrants trying to enter the U.S. by boat in South Florida and the Keys is the highest it’s been in nearly a decade. Hundreds of migrants on boats were stopped in the last few months. There have been nearly 2000 similar apprehensions since October. According to U.S. Border Patrol, most of those migrants were from Cuba and Haiti.

The Associated Press contributed to this report.