A trip to the Florida Keys is all about sun, sand, and saltwater—all things you’ll find in abundance in this tropical paradise. Saltwater, in particular, is an integral part of the vacationer’s Florida Keys experience, from fishing and boating to snorkeling and scuba diving.

But saltwater isn’t the only aquatic attraction worth your time. The Blue Hole on Big Pine Key is a freshwater lake formed in an abandoned rock quarry and is the largest—and only—freshwater lake in the Keys. As such, many rare and endangered species call this area home.

About the Blue Hole


The Blue Hole is in the National Key Deer Refuge on Big Pine Key, one of the largest islands in the Florida Keys. The refuge covers 9,200 acres and was established to preserve and protect the endangered Key deer: the smallest subspecies of the North American white-tailed deer, unique to the Florida Keys.


a Key deer at Blue Hole on Big Pine Key
Key deer | Photo courtesy of oceano_magico

Visitors who flock to the Blue Hole for a glimpse of local wildlife are rarely disappointed. In addition to Key deer, you may see wading birds, Peregrine falcons, turtles, Lower Keys marsh rabbits, green iguanas, and of course, the American alligator.

Other Activities

There are two nature trails near the Blue Hole. The Watson Trail is a 2/3-mile-long loop through several distinct habitats, including freshwater wetland, pine rockland, and hardwood hammock. The Mannillo Trail is a shorter out-and-back trail that leads to an observation platform overlooking a freshwater wetland area. Take a seat on one of the benches along the Mannillo Trail and spend a few minutes relaxing in the peaceful environment.

Stop by the National Key Deer Refuge Visitor Center for information about the refuge, suggestions for the best birding locations, and informational exhibits and displays. Join a qualified volunteer for guided walks, bike rides, and kayak excursions. The visitor center also offers loaner pairs of binoculars, so you can get a close-up view of any wildlife you encounter.

Know Before You Go

Boy scouts at the Blue Hole.
Observing the Blue Hole | Photo courtesy of Allen Pinkley

Dress for Success

The Florida Keys have sun in spades, which isn’t always a good thing! Protect yourself against sunburns by using sunscreen, sunglasses, and hats to minimize UV exposure. Temperatures can hit the 80s and 90s during summer and early fall, so wear light clothing and bring plenty of water to keep yourself hydrated. Consider bringing bug spray to protect against mosquitoes.

Be Cautious and Aware

Be cautious when hiking in the area. Several poisonous plants call this region home, including the poisonwood tree, which causes a similar reaction to poison ivy if skin contact occurs. Venomous diamondback rattlesnakes have also been seen. Though none of these natural hazards are cause for alarm, it’s important to familiarize yourself with the wildlife at the visitor center before venturing out.

Respect Local Wildlife

A warning sign saying Please Do Not Feed Wildlife.
Photo courtesy of Rusty Clark~ 100k Photos

Please refrain from feeding the wildlife, including Key deer and alligators. Feeding the deer harms the population by habituating them to humans; do your part to keep these animals healthy. Dogs are welcome at the refuge if they are kept on the nature trails and on a leash less than six feet long at all times.

If you’re planning a trip to Big Pine Key, the Blue Hole is definitely worth a visit. This unexpected freshwater oasis provides an incredible opportunity to see unique Florida Keys wildlife in a variety of beautiful habitats. Don’t miss out on this memorable addition to your vacation!

Featured photo courtesy of Juliegever

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Author: Madison Schultz

Madison grew up in western Kansas with a family that loves to travel. She is a highly accomplished roadtripper, having driven from western Kansas to Portland twice—the second time, in a moving van. Her favorite places include Rothenburg ob der Tauber, Innsbruck, Florence, York, Edinburgh, Ely, the San Juan Islands, Taos, and Lawrence.