Climbing Down to The Gulf Sinkhole

The Gulf is a massive sinkhole created by a collapsed cave found in Mark Twain National Forest about 33 miles north of Poplar Bluff.

It is an amazing sight to see and worth the stop if you are in the area visiting Clearwater Lake, Lon Sanders Canyon, or staying the night at Markham Springs Campground, which I will talk about in a future blog post.

Informational sign near the front of The Gulf describes its origins in detail. — *An informational sign near the front of The Gulf describes its origins in detail.*

What It Is?

The Gulf known locally as The Blue Hole is a unique feature as a water-filled sinkhole created when a cave collapsed.

Dimensions of The Gulf

The air-filled opening is a mere 20 feet wide, 100 feet long, and 50 feet deep. It is part of an impressive underground cave system that extends at least 2,100 feet in horizontal length. A few stalactites and occur high on the ceiling, and the water drips constantly from the far end of the passage. Water depth ranges from 140 to 220 feet. Much of that distance is impassable due to high water.

How It Is Different from a Natural Spring

*Another informational sign explains the drainage area for The Gulf.*

The surface of the water stays relatively warm, between 61 to 67 Fahrenheit. About 50 feet down it is a chilly 59 degrees Fahrenheit. Researchers believe this variation in temperatures is due to solar radiation at the entrance to the sinkhole, while temperatures at greater depths are closer to those of groundwater.

The Gulf lies within the Big Brushy Creek drainage, which is a tributary to the Black River, yet it is uncertain how The Gulf interacts with the surrounding waterways.

Geologists believe the water drains from a relatively small area since it lacks minerals. Also, the blue hole quickly fills up with water after a storm, and sometimes water has been seen flowing out of the sinkhole.

Water Quality

The blue color of the water is due to sunlight interaction, water clarity, and extreme depth. Crystal clear water is deceptive because entry into the water quickly results in a rapid clouding of the water by sediment along the cave wall. This is why it is extremely dangerous to swim in its waters. Also, you might disturb some of the few blind cavefish that live in its waters.

My Time Here

I parked at the lot and The Gulf can be seen just a few feet away from the parking area, I stopped and looked into it then noticed a trail and followed it all around outside of The Gulf.

Trail Around

This trail follows the wooden fence that surrounds the hole. This helps to keep animals from falling into it. I read somewhere a car might be deep in its waters. It would damage the cave to take it out.

I liked the woods walk even though The Gulf was at a distance. I saw a box turtle walking across the path and a deer jump into the woods. When I finished the loop trail I noticed another small trail heading down to The Gulf.

Look for this small trail near where you enter the area at. — *Look for this small trail near where you enter the area.*

Cautious Walk

This trail heads down pretty fast so be very careful going down it if you want a closer look. I did it slowly and was rewarded with a close-up view of the hole.

This trail becomes steep so I had to watch my footing.

I didn’t see any snakes luckily but scared a lot of frogs that kept jumping all around me into the water.

*In front of the blue water of The Gulf*

It is a bit eery down there all alone. You look up to high cliffs above you and below you is this blue hole that goes way down. It was a strange experience.

There is a ledge that you can walk along if you feel inclined I was just happy to take in the view.

I took my time going up and then was ready to head out. This is not a long hike, just a cool place to check out.

Nearby Cemetery

Carson Hill Cemetery is on Carson Hill Road on your left before the Blue Hole Road to The Gulf. This cemetery is the final resting place for Missouri Gov. Mel Carnahan who died in 2000 in a plane crash.

Carnahan’s name was still on the ballot for senator for Missouri in the 2000 election. His wife took his place and John Ashcroft who ran against him lost but became U.S. Attorney General in the President George W. Bush Administration.

DETAILS

The Drive: Take Interstate 55 south to exit 174 B for US 67 South for almost 50 miles to the exit for M-34. Then take the Mo-34 toward Piedmont and in this town make a left onto Mo-49 south. After driving through Mill Spring and crossing over the Black River look for Carson Hill Road or County Road 442 on your right. This road becomes County Road 443 and Carson Hill Road veers left and goes to Carson Hill Cemetery.

Make a right turn onto Blue Hole Road. I didn’t see the sign but it was the only road on the right after Carson Hill Road. If you reach Big Bushy Creek you have gone too far.

You are on Blue Hole Road for a short drive. It is a narrow lane, but it is well graded. I found the Carson Hill Road a bit rough since you are on gravel going up and down hills.

Hours: Sunrise to Sunset

Admission: Free

Address: Mill Spring Township, MO 63952