Oblique view closer to Sideling Hill than the photo at left. In this photo, the Exhibit Center and pedestrian bridge are clearly visible. (Photo: Federal Highway Administration , Maryland Division)
View west from the pedestrian bridge. (Photo:Maryland Geological Survey)
Oblique view of the north side (south-facing) side of the
road cut, showing the syncline that underlies Sideling Hill.
(Photo: Paul Breeding for the Maryland Geological Survey, 1986)
The I-68 road cut through the crest of Sideling Hill in western Washington County , Maryland , created one of the best geologic exposures in the northeastern United States . Revealing a cross section through a synclinal ridge, this massive cut has proven to be a significant educational and research tool and tourist attraction. Aside from the geology, however, many visitors ask questions about the construction of this road cut and the Sideling Hill Exhibit Center, which has now moved to Hancock, MD. This fact sheet attempts to answer many of those questions.
When was this part of the Interstate 68 and the road cut constructed?
Excavation began in April 1983, b lasting was completed 16 months later in August 1984; the completed highway was opened in August 1985.
How deep is the Sideling Hill road cut?
The cut is 340 feet deep from the ridge crest to road level. Surface elevation at the ridge crest is about 1,620 feet and at road level about 1,280 feet.
How wide is the road cut?
The road cut is 200 feet wide at road level and 720 feet at the top of the cut.
How was the road cut made?
Blasting with a total of approximately 2,600 tons of explosives was the major method used to break up the rock, which was then removed with giant earthmovers.
How much rock was excavated from Sideling Hill?
4.5 million cubic yards, or about 10 million tons, of rock were removed to make the cut through Sideling Hill. Most of the rock was crushed and used to make the road bed leading to the cut.
Were there any serious accidents or fatalities during the construction of the road cut?
What is the purpose of the horizontal ledges on the face of the Sideling Hill road cut?
The ledges, or benches, are 10 to 20 feet wide and slant towards the mountain to catch and hold falling rocks. The four ledges on each side of the cut are 80 feet apart vertically.
What was the cost of making the Sideling Hill road cut?
The road cut and miles of road cost $20.1 million, $10 million less than the next competitive bidder. The project was paid for with 90% Federal monies and 10% State monies.
Who was the contractor for making the Sideling Hill road cut?
The prime contractor was Holloway Construction Company of Wixon , Michigan .
Was a tunnel ever considered in the planning?
The cost of continuous maintenance and upkeep would make a tunnel more expensive and a poor choice. Also, people hurt in accidents would be much more easily evacuated from the road cut by helicopter.
How much did the Sideling Hill Exhibit Center cost?
The building cost $1.8 million. The entire complex of the center, parking lots, water and sewer systems cost about $5.5 million. The project was funded entirely by State monies.
How long did it take to build the Exhibit Center?
The Exhibit Center was begun in the spring of 1989, and the building was completed in July 1991. Architect Henry Dubay, of Greiner Engineering, Baltimore , Maryland designed the Exhibit Center .
When was the Sideling Hill Exhibit Center opened to the public?
Governor William Donald Schaefer dedicated and opened the Sideling Hill Exhibit Center to the public on August 2, 1991. It is now permanently closed.
When was the Sideling Hill Exhibit Center closed to the public and where is it now?
The Exhibit Center at Sideling Hill was permanently closed in 2009 due lack of funds. The exhibit was move to the Hancock Museum at 42 W. Main St., Hancock, MD 21750-1107; (301) 678-6236. For more information, visit http://www.hancockmd.com/. Be sure to visit the newly renovated Sideling Hill Exhibit, a short drive from the road cut in Hancock, MD.
Some links for more information:
A printable version of FactSheet 17 is available in Adobe Acrobat PDF format
Prepared by Jim Reger
Compiled by the Maryland Geological Survey, 2300 St. Paul Street, Baltimore, MD 21218
This electronic version of "FactSheet No.17" was prepared by R.D. Conkwright, Division of Coastal and Estuarine Geology, Maryland Geological Survey. Please send comments on this page to Dale Shelton (firstname.lastname@example.org)