In the Apalachicola National Forest just south of Tallahassee, Leon Sinks Geological Area offers a delightful introduction to the wonders of karst topography.
Karst is a landscape that happens through deep erosion of a soft rock such as limestone, and it leads to the most unusual visual treats as water flows into, out of, and through the Swiss-cheese holes that occur within karst. Much of Florida’s water – our aquifers – is within karst, which means there is little to no filtration as groundwater seeps into the spongy limestone bedrock and starts flowing from point to point.
Years ago, you could take a glass-bottomed boat ride across Wakulla Springs, just a few miles to the southeast of Leon Sinks. No more. The clarity of the spring now suffers as groundwater contaminated by nitrates – from leaching septic tanks to lawn fertilizer – works its way through the Woodville Karst Plain, of which Leon Sinks is a major feature, to one of the largest springs in the world. At Leon Sinks, you’ll see pools of water in a variety of colors at the bottom of deep sinkholes. You can stare right into a watery cave, watch water vanish in a losing stream, and see it pop up again in a river rise. The trail system is rugged but fun, and filled with botanical beauty, especially in early spring.
Length: 4.4 miles (outer loop)
Lat-Long: 30.309781, -84.346486
Fees / Permits: entrance fee
Difficulty: moderate to difficult
Bug factor: low to moderate
Restroom: at the trailhead
Camping is not permitted at Leon Sinks. The trail system consists of two loops – the 3.1 mile Sinkhole Trail (blazed blue) and the 2.3 mile Gum Swamp Trail (blazed lime green)- and a 0.5 mile cross-trail that they both share to make their loops. I typically hike the trail system counter-clockwise, so I can make the decision at the cross-trail whether I want to continue on the outer loop or not. This hike describes the full outer loop.
Check out the interpretive information at the trailhead before you start your hike. This is a simply fascinating place and getting to understand karst a little better before you begin climbing in and out of sinkholes will greatly enhance your appreciation for the weird landscapes that lie ahead.
From Tallahassee, drive south for 4 miles on US 319 (from its junction with SR 61 in the city). The trail entrance is prominently on your right.
A short connector trail leads from the trailhead near the restrooms to the main loop. Turn right to begin your traverse of the Sinkhole Trail. This is an undulating landscape topped with longleaf pine and wiregrass, the classic forest that once covered the southeast and has now shrunk to a tiny fraction of its original range. We’re fortunate that the Apalachicola National Forest, established in 1937, protects so much of it. The blue blazes lead you down a flight of stairs into Dry Sink, a depression filled with dogwood and Southern magnolia trees.
Notice the wooden posts announcing your arrival at each sink, and its name. The trail rises up and loops around to an overlook with a bench over deep Turner Sink. Crossing an old jeep road, you circle the left side of Cone Sink and pass Palmetto Sink, reaching Back Sink. Slip down the side trail here to take a peek into the sink and see its two deep throat-like bowls at the bottom.
After 0.5 mile, you pass Far Sink. As you walk along the ridge, watch for a glimmer of aquamarine through the trees below, and don’t miss the turnoff on the left to Hammock Sink. This is one of my favorite stops on the hike, and well worth your time to sit, relax, enjoy, and if you’ve brought your camera, take a lot of angles on this one. Hammock Sink is a pool of aquamarine blue, crystal clear and tinted by nature itself. The color is simply breathtaking for a natural feature. Dogwoods rim the ridge above, lending a splash of spring color. A boardwalk and observation deck provide excellent perspectives on this beauty spot.
Climb up and out of Hammock Sink on the trail to the left to pass Tiny Sink a few moments later. You’re on your way to another showy display of karst, the Big Dismal Sink. From its size, you’ll see why the trail doesn’t drop into it—your view is from an observation deck at the top of this 130 foot deep sinkhole, the deepest in the Woodville Karst Plain. It is a true karst window, a cylindrical viewport into the aquifer with no safe access to the water below. Spontaneous waterfalls occur when groundwater seeps from above the clay cap of the forest soil and drips down through the ferns and other vegetation into this deep, dark sink.
Rising into longleaf pine sandhills, the trail passes through an area where wildflowers are especially showy in spring and fall, passing dry Field Sink. Climbing up into a shady upland forest at 1.2 miles, you head straight for Big Eight Sink—don’t plunge in! Next is Magnolia Sink, trimmed along the edges with Southern magnolias and weird rock formations. A bench gives you a place to take a rest near Black Sink. The trail pops back out into the sandhill habitat for a pleasant rolling stroll before reaching the shady forest again.
Just past a clearing with several benches, you have a decision point – follow the high water route or head down into the valley for a peek. The crossing over Lost Stream Sink has been removed, so it’s only a peek. A lost stream is a stream that slowly vanishes into the earth due to the karst below—it ends up flowing underground.
It’s a short ramble through the forest to your decision point on the trail system, the junction with the Crossover Trail and Gum Swamp Trail at 2.1 miles. If climbing in and out of sinkholes has worn you out, here’s the good news—there isn’t any more of that along the trail system. So take your pick here whether you want a 3.1-mile hike (taking the Crossover Trail now) or a 4.4-mile hike. The Crossover Trail passes through the heart of Gum Swamp on a boardwalk, where the shapely trunks of the trees reflect against the dark water. The outer loop of the Gum Swamp Trail skirts its edge but has its own delights.
This spot is geologically intriguing, since you cross a natural bridge to get to the trail junction. Fisher Creek – the Lost Stream – rises up as a spring at a base of large rocks and flows away past a rocky bluff. A bench sits off to the right along the Gum Swamp Trail to take in the scenic view. Turn right to start your journey down the Gum Swamp Trail, and take a moment to step out on the rocky bluff so you can see where the stream rises out of the ground.
While the Gum Swamp Trail offers less in the way of cool geology, it’s here you’ll find botanical beauty, especially during early spring when the wild azaleas are in bloom. The ones I’ve seen here are unlike any others I’ve seen in Florida. They open up into giant puffs, with azalea blossoms forming perfect orbs suspended in air along the stems. Pine cones cover the forest floor, and the footpath is on a nice layer of pine duff. You pass a marker with a lime green arrow.
After you cross an old jeep road, the forest becomes much denser, with loblolly and longleaf pines towering overhead. Gum Swamp is visible in the distance through the trees to the left. But you’ll have your swamp encounters soon. The trail reaches Bear Scratch Swamp and a bench overlooking the view at 2.9 miles. At South Swamp, look for a pine and water oak that have grown intertwined, right near the sign. The trail winds past Shadows Swamp, a good place to stand and listen for birds.
The Gum Swamp Trail meets back up with the Crossover Trail at 3.6 miles. Turn right to stay on the outer loop heading clockwise. There is one last karst formation to visit – the Gopher Hole. It’s down a side trail on the right and well worth the short ramble. It’s a water-filled cavern that indeed looks like a gigantic gopher hole, and you can stare right into it and watch drops of water fall from the cave ceiling and create ripples across the placid surface. Bring a flashlight if you want to peer further inside.
Returning up the Gopher Hole side trail, turn right. Within a few minutes, you’re back at the beginning of the Sinkhole Trail. Turn right to exit out to the parking area, completing your hike of 4.4 miles.
0.1 Loop trail junction
0.2 Turner Sink
0.3 Cross jeep trail
0.4 Back Sink
0.5 Far Sink
Big Dismal Sink
1.2 Big Eight Sink
Lost Stream Sink
2.1 Crossover / Gum Swamp trail junction
2.7 Arrow marker
2.9 Bear Scratch Swamp
3.4 Shadows Swamp
3.6 Crossover Trail junction
4.1 Gopher Hole side trail
4.3 Loop trail junction