Mike Emanuel's Cave Diving Page

Isabella Spring
(The Black Hole)

Photo of the Black Hole

Isabella Spring facing Northeast

LOCATION: (lat. 28°23'53.7" N., long. 82°40'27.1" W.)

The spring is located off old Dixie Hwy. in Hudson, FL. in a wooded swamp just NorthEast of the Withlacochee Electric substation.


Isabella Spring has come to be known as "The Black Hole" among cave diving folks. I think this nickname came from a combination of it's location back in a swamp, the narrow cave passages and the entrance which is clogged with spooky looking tree limbs draped in long stringy algae. It's a small cave system with approxamately 330 ft of surveyed passage. The spring has a gentle flow that is affected by the tides and can siphon for several hours after a high tide. Visibility is quite good (30ft+) in the cave and basin and the water usually has a blueish tint, indicating that there must be at least a partial connection to the aquifer. All passages are rather tight and easily silted out due to the low flow; a two man team is perfect, threes a crowd.


Upon entering the pool one immediately comes across a rocky sink at the south end of the basin, this drops down about 50ft and pinches off into the silt. Swimming north across the cracked limestone floor of the basin you come to another sink with several logs in it. Dropping down to 35ft reveals a tall narrow passage with a permanent guideline on the left. This rocky staircase goes to 60ft where it intersects with the main passage in a tee shape, the passage to the right has no line and goes about 20ft into a room with a small floor pit. The guideline for the upstream passage bears left through a restriction and lots of catfish, the cave then opens up and you can take either the over or under line, both reconnect just before going through the major restriction at 105ft.Take a right, ( the hole off to the left, gets too small, I've tried) the passage is now wider but only 3 to 5ft high, after another right hand turn the line disappears under a huge sheet of rock, ascending up the backside of it leads you to the top of the dome room at 85ft. Go over the edge of the rockpile to the end of the line at 110ft, here is the source of the clear blue water. Look around, I have left the fossilized rib bones there on the ground, hopefully you will too.

Click Here For A Map Of The Black Hole

Spooky basin looking up from cave entrance

Dark limestone walls of the Black Hole

Fossilized Dugong ribs on floor of Dome Room