SANDY HOOK -- More than 100 seals were lounging Sunday morning on Skeleton Hill Island on Sandy Hook.

Over 100 seals are currently hauling out at Sandy Hook's Skeleton Hill Island on Sandy Hook Bay. Park at Lot C, cross... Posted by Gateway National Recreation Area on Sunday, February 21, 2016

The National Park Service's Gateway National Recreation Area shared a photo of the seals and invited visitors to Sandy Hook to have a look.

By about 2 o'clock, a crowd had gathered to get a look at the marine mammals, which were already headed back into the water.

A seal was also spotted Monday on the Hudson River, drying off on an patch of ice. Firefighters helped it back into the river.

NJ Advance Media photographer Ed Murray contributed reporting.

Myles Ma may be reached at mma@njadvancemedia.com. Follow him on Twitter @MylesMaNJ. Find NJ.com on Facebook.