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Rock House, Ohio’s Largest Natural Arch & Tunnel EarthCache

A cache by BiT Message this owner
Hidden : 06/07/2008
1.5 out of 5
2.5 out of 5

Size: Size:   not chosen (not chosen)

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Geocache Description:

This EarthCache highlights a unique but misunderstood geological feature within the Hocking Hills region. This EarthCache was developed under special permit from the Ohio Department of Natural Resources, Division of Parks and Recreation with special assistance from Chris Grupenhof. This park is open Daylight Hours Only and the Collection of Specimens, Either Biological, Cultural, or Mineral is Strictly Prohibited. Please stay on designated trails, see trail map by clicking here.

Remember as always, Leave No Trace.

Parking (included as a child waypoint) is available at the
Rock House Parking Lot at N 39° 29.728, W 082° 36.740.

Rock House, The Bigger Opening

Rock House, The Smaller Opening

Inside or Under Rock House

Rock House is a natural arch and a natural tunnel but not a natural bridge. It is by far the longest known natural arch and natural tunnel in the State of Ohio. Also it is the only know arch in the state with windows opening through the side.

How do you define a natural arch?

An arch is a horizontal remnant of exposed bedrock supported at two opposing locations spanning an opening created by erosion. Not every hole in the bedrock is considered an arch. An arch must meet this measurement criterion. The span (horizontal measurement of the opening) and clearance (vertical measurement of the opening) must be greater than or equal to 6 feet with neither measurements being less than a foot. Windows are openings that are smaller than measurement criterion. They are also referred to as windows, gothic windows, lighthouses, holes, and etc…

How do you define a natural tunnel?

A natural tunnel is a natural arch whose width, the horizontal measurement perpendicular to the front face of the arch, is greater than or equal to three times its span.

How do you define a natural bridge?

A natural bridge is a natural arch that spans a valley formed by erosion. A natural bridge is always a natural arch, but a natural arch may not be a natural bridge.

How did the Rock House form?

Rock House was formed by the widening of a vertical crack which separated a large block of Black Hand sandstone from the main cliff above a small tributary of Laurel Run. This created a passage nearly 200’ long, 40’ high, and 20’ wide. Erosion and expansion of secondary joints crossing the main joint has led to the formation of Rock House’s distinctive gothic windows. This didn’t happen overnight, it took millions of years during the Pleistocene epoch.

Some modern, in geological terms, history of Rock House.

Archaeological evidence from Rock House indicated that the prehistoric Native American’s utilized this location. There are two theories about the man-made indentations in the wall face. One is the the Native Americans constructed these as small ovens to cook meals. They also created troughs in the cave's floor, which collected water to help provide the residences with a water supply. The other is that they were turpentine stills. Turpentine was a common resource for that local Native Americans. It was used as a medicinal purpose, both internally and externally, for a wide variety of illnesses and injuries. The Native Americans would place bits of pitch pine wood in the indentations. On top of that they would layer of flat sandstone. Finally on the top a fire would be built. The heat would drive the sap out of the wood, which would then flow through the channel and pour into waiting vessels.

In the not-so-distant past, Rock House was also referred to as Robbers Roost. It seems that during the early 1800s local robbers, horse thieves, murderers, and bootleggers made their temporary residence here. The only know fatal bear attack in Hocking County happed at Rock House. William Reynolds, one of the earliest landowner used Rock House for a barn for his livestock. Then one evening while walking to do his evening chores he encountered a bear which attacked. Severely mauled, Mr. Reynolds survived and was only to later to die from complications and infection the following week. Then in 1835, an ambitious Colonel Rempel from Logan, Ohio erected a hotel nearby hoping to capitalize of the increased tour activity in the area. The hotel was had 16 rooms, a grand ballroom, a horse livery, and a US Post Office. The hotel stood where the present day shelter house stands.

To claim a find, please email me the answers to the questions below. Also you will need to upload a picture of yourself holding your GPSr with Rock House in the background with your find log. Logs that do not follow the finding requirements will be deleted.

Question 1: How many windows does Rock House have in it’s wall?

Question 2: How many indentations in the wall face are there?

Question 3: At N 39° 29.862, W 082° 36.785 and N 39° 29.887, W 082° 36.765 are two additional geological features, what are they?


Camp, Mark J.
2006 Roadside Geology of Ohio.Mountain Publishing Company, Montana.

Hansen, Michael C.
1988 Natural Bridges in Ohio, Ohio Geology.

2007 Rock House. Ohio History Central,

Additional Hints (No hints available.)