McConnells Mill State Park was chosen by the Pennsylvania Department of Conservation and Natural Resources (DCNR) and its Bureau of Parks as one of “Twenty Must-See Pennsylvania State Parks”.
McConnells Mill is located near Moraine State Park. I started early one August morning and managed to visit both parks in the same day. A conversation with a friend afterwards prompted me to schedule a return visit. This month, I spent an extra seven hours exploring the park and I was astounded by how much I missed on my first visit. I recommend giving this park a full day to explore on its own. There are nine miles of hiking trails throughout the park.
The town of Slippery Rock and the surrounding gorge were named for one particularly slick rock located under the Armstrong Bridge. This area was a natural source of oil in the 1800s. Eventually, the oil was invaded by groundwater and the wells were abandoned.
The water along Slippery Rock Creek is very deceptive. Although it can seem quite tame, the water is in fact very turbulent and moves fast enough to qualify as whitewater. Swimming is prohibited in this park. Regardless of the warnings posted throughout the park, someone drowns every year.
Rock City (McConnells Mill Road)
Daniel Kennedy built his first gristmill in 1852. Within the same year, it was destroyed by fire and was not rebuilt until 1868. The mill was purchased by Thomas McConnell in 1875. McConnell renovated the mill by replacing the waterwheel with water turbines and the grinding stones with rolling mills. One of the first rolling mills in the country, it processed corn, oats, wheat and buckwheat for local customers. Antiquated equipment and plummeting profits caused the mill to close in 1928.
The McConnells Mill Covered Bridge dates back to 1874. The bridge is listed on the National Register of Historic Places and is still in use today.
To the left of the covered bridge is the Kildoo Trail. In addition to the rapids along Slippery Rock Creek, there is also a series of cascading waterfalls known as Kildoo Falls suspended above a wooden footbridge.
After climbing the outskirts of this waterfall, I’ve determined that the best photos are taken from the bridge.
Slippery Rock Creek Gorge was formed thousands of years ago by glacial melting and is a national natural landmark.
The Hells Hollow area offers two trails next to each other (Hells Hollow Trail and Slippery Rock Gorge Trail). The Hells Hollow Trail is about 1/2 mile long and leads directly to Hells Hollow Falls.
Vanport Limestone and the old iron industry flourished in the mid-1800s.
Lawrence Iron Furnace Slag Piles
This section of Hell Run was originally a cave, until the roof collapsed and created a flume.
Lime kiln to the right of the falls
The Hells Hollow Trail leads down a flight of wooden steps to the foot of the waterfall. The current is very swift and rock hopping is difficult. Waterproof hiking boots are a necessity if you want to get a head-on view of the falls.
Hells Hollow Falls (cascade waterfall)
To the left of the Hells Hollow Trail is the Slippery Rock Creek Gorge Trail, which spans about seven miles and will lead to most of the major sites in McConnells Mill. This is a strenuous, physically demanding trail that offers many challenges for the experienced endurance hiker. The Slippery Rock Gorge Trail is part of the North Country National Scenic Trail, which spans from New York to North Dakota and encompasses seven states. This trail leads directly to the top of the gorge and hikers will climb and drop, twist and turn, and climb and drop again many times during the narrow ascent. The trail is toughest from Hells Hollow to Walnut Flats.
Acid mine drainage along Hell Run
Cave near Walnut Flats
Walnut Falls (cascade waterfall)
Breakneck Falls is not a misnomer. Photographing these falls was quite challenging. I had to lay on my stomach hanging off a large rock! There is a path to the right of Breakneck Bridge, but it was too steep and slippery to attempt the descent to the bottom.
Breakneck Falls (cascade waterfall) and Breakneck Bridge
Eckert Falls (cascade waterfall)
If you are willing to make a steep uphill climb, you will discover there is another waterfall above this one.
Cleland Rock is a ledge composed of Kittanning Sandstone and is situated on the highest part of the rim of the gorge. The road leading up to the vista cuts through a corn field and is composed of gravel and mud. Due to the deep ruts in the path, travel by car may be impossible.
Alpha Falls, also known as Spill Way Falls and Gardiner Falls, spans a height of 34 feet. This waterfall is on the Alpha Pass Trail.
During my visit, I saw many chipmunks, a field mouse, a great blue heron, and even these two lovebugs!
I was pleasantly surprised by the clumps of scilla dotting the landscape. I did not expect to see any wildflowers this early in the year.
Lack of trail access caused me to miss at least two noteworthy waterfalls. Grindstone Falls are roughly three miles south of the mill on Grindstone Run, and Skunk Run Falls are on Skunk Run near the Armstrong Bridge.
Update: In May of 2012, we returned to McConnells Mill after learning how to safely hike to Breakneck Falls. It’s not the way it seems! Read about our adventure at