There is precious little fresh surface water in the Florida Keys, but Big Pine Key is one of the places it exists.
That’s thanks to the Swiss-cheese nature of karst bedrock found in the limestone reef rock of the Keys, which stores rainwater in crevices and holes.
A bounty of fresh water is what helps support the population of Key deer and other wildlife in the Lower Keys.

Found nowhere else on Earth, the Key deer is the world’s smallest deer. Grown bucks may be no taller than a German shepherd.
In 1957, only 50 Key deer remained. To prevent species extinction, 84,351 acres on Big Pine Key and on 24 other nearby islands was permanently protected as National Key Deer Refuge.

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Overview
Location: Big Pine Key and surrounding islands
Visitor Center: 24.670391, -81.35443
Address: 30587 Overseas Hwy, Big Pine Key
Fees: Free
Restroom: At the visitor center
Land manager: National Key Deer Refuge
Phone: 305-872-0774
The refuge is open daily from a half hour before sunrise to a half hour after sunset. Visitor center open 10-3 Wed-Sat.
All areas are day use only. For your safety, stay on established trails. Insect repellent is a must.
Report wildlife emergencies such as injured or dead Key deer or aggressive animals to Florida FWC immediately at 888-404-3922; press Monroe County extension.
Directions
The visitor center is on the bay side of US 1 on Big Pine Key at mile 30.5, north of Key Deer Blvd.
About the Refuge
The Key deer population has rebounded to nearly a thousand deer. They roam through the populated areas of Big Pine Key as well as through the woods.
There are three nature trails along Key Deer Blvd on Big Pine Key where these diminutive deer are frequently seen. The most likely place to see them is at Blue Hole.

Blue Hole
For the easiest wildlife watching at National Key Deer Refuge, visit the trail and observation deck at Blue Hole, a cenote-like pond that is the largest body of fresh water in the Florida Keys.

A little farther up the road, the Wildlife Trails lead into natural pine rocklands and rockland tropical hammock habitats where Key deer forage.

Fredrick C. Mannillo Jr. Nature Trail
Key deer browse the understory of a pine rockland explored on this short accessible interpretive trail within National Key Deer Refuge.

Jack C. Watson Wildlife Trail
Rare pine rockland and rockland tropical hammock are key habitats for Key deer along this immersive interpretive loop on Big Pine Key.

Stick to established trails in National Key Deer Refuge. There are a large number of poisonwood trees and some manchineel trees in these rare rockland habitats.
Both native trees have highly toxic leaves and bark, and their fruits are deadly to humans. Leaving the trail puts you at risk of brushing into them.

While developed trails are on Big Pine Key, old roads into the preserve can be followed at several other locations.
These public access points are on Big Pine Key, No Name Key, and the Sugarloaf Keys. Ask Visitor Center staff for a map of the outlying trails.

We detailed most of these remote trails in 50 Hikes in South Florida. Of them, the Long Beach Trail has since been abandoned.
It sustained significant hurricane damage and will not reopen, although you are permitted to walk down the shoreline.

Of course, you may see Key deer wandering around anywhere on Big Pine Key, No Name Key, and the neighboring islands.
Tiered speed limits are in effect on all roads with lower speeds after dark. Please drive with caution through Key deer habitat.
Please do not feed the deer, as they lose their natural fear of humans and put themselves at danger.

Trail Map

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See our photos of National Key Deer Refuge
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More worth exploring while you’re in this area.

Overseas Heritage Trail, Lower Keys
38.0 miles. Between Key West and Bahia Honda Key, this segment of the Florida Keys Overseas Heritage Trail crosses many historic railroad bridges in view of mangrove-lined shores.

Bahia Honda State Park
Long known for its natural beaches, Bahia Honda State Park continues to heal after the ravages of Hurricane Irma stripped much of its tropical vegetation

Key West Tropical Forest & Botanical Garden
With boardwalks and natural footpaths winding amid curated collections against a backdrop of natural Florida Keys habitats, the Key West Tropical Forest & Botanical Garden is a delightful natural destination.

Sonny McCoy Indigenous Park
Within sight of the Atlantic Ocean, Sonny McCoy Indigenous Park is a rare patch of green space in the city of Key West, with native trees and a natural freshwater pond.