Sideling Hill

First, a correction worth knowing before you plan a trip. Sideling Hill in Maryland is not on I-70. The road that cuts through it is I-68, the National Freeway, along with old US 40. At Hancock, Maryland, I-70 turns north toward Breezewood and the Pennsylvania Turnpike. I-68 branches west and crosses Sideling Hill about 5 to 6 miles past Hancock (Wikipedia; AARoads). If someone tells you Sideling Hill is an I-70 climb, they have the wrong ridge.

What makes this spot famous is the road cut, a notch blasted 340 feet deep through the crest of the ridge. The ridge surface at the cut sits around 1,620 feet; the road runs through at about 1,280 feet (Maryland Geological Survey, Fact Sheet 17). The cut is 200 feet wide at road level and opens to 720 feet wide at the top. Drivers know it as a landmark first and a grade second, because the cut replaced the old steep climb that the National Road used to make over the top.

The crossing connects Hancock and the I-70/I-68 junction westward toward Cumberland and the Allegheny region of western Maryland (AARoads; Wikipedia). It stays open year-round. There is no scheduled winter shutdown here; when the road closes it is because of a crash or weather, not a calendar. For a sourced grade percent or the length of the I-68 climb, none was published by MDOT or FHWA, so this guide does not give one. The cut took out much of the old steep approach, which is part of why a hard grade number is hard to pin down.

• The crossing is on I-68 (the National Freeway) and old US 40, not I-70; at Hancock, MD, I-70 heads north and I-68 branches west (Wikipedia; AARoads)
• The road cut is 340 ft deep, 200 ft wide at road level and 720 ft wide at the top (Maryland Geological Survey, Fact Sheet 17)
• Ridge surface at the cut is about 1,620 ft; road level is about 1,280 ft (Maryland Geological Survey, Fact Sheet 17)
• The ridge's overall high point, Fisher Point, is 2,310 ft, up in Fulton County, PA, away from the highway (Wikipedia)
• Building the cut took about 2,600 tons of explosives and removed roughly 4.5 million cubic yards of rock, blasted Apr 1983 to Aug 1984 (Maryland Geological Survey, Fact Sheet 17)
• The project cost about $20.1 million, 90 percent federal and 10 percent state (Maryland Geological Survey, Fact Sheet 17)
• Maryland has no mandatory tire-chain law and posts no chain-control levels; chains are allowed for safety in snow or ice but not required (Md. Transp. Code 22-405.2)

Maryland runs no chain-control season the way the western states do. There is no posted "chains required" level here, nothing like Caltrans R1/R2/R3 or CDOT's system. The statute simply permits tire chains of reasonable proportions on any vehicle when they are needed for safety because of snow, ice, or other conditions that tend to make a vehicle skid (Md. Transp. Code 22-405.2). Chains are allowed, not ordered, so there is no season to open or close. Studded tires are the one thing tied to dates: they are permitted November 1 through March 31, and only for vehicles registered in Allegany, Carroll, Frederick, Garrett, or Washington counties (Md. Transp. Code 22-405.2). Maryland also does not run designated chain-up or brake-check areas with mile markers on I-68 or I-70, so do not expect a numbered pull-off. When the road closes it is incident-driven, from a crash or weather, and Maryland CHART (chart.maryland.gov) tracks the real-time status.

Before the interstate, US 40 and the National Road went over Sideling Hill the hard way, with a steep grade on each side and a sharp hairpin turn at the crest (FHWA Highway History; Wikipedia). It was known for a long time as a steep, dangerous climb. The fix was to cut straight through the ridge instead of going over it.

Excavation of the I-68 road cut began in April 1983. Blasting finished about 16 months later, in August 1984, after roughly 2,600 tons of explosives took out about 4.5 million cubic yards of rock. The prime contractor was Holloway Construction Co. of Wixom, Michigan, and the work cost around $20.1 million, split 90 percent federal and 10 percent state. The highway through the cut opened in August 1985 (all from Maryland Geological Survey, Fact Sheet 17). On August 2, 1991, Gov. William Donald Schaefer dedicated the Sideling Hill Exhibit Center at the cut, which showed off the folded rock layers exposed by the blasting. The center closed in 2009 for budget reasons and the exhibit moved to Hancock (Maryland Geological Survey, Fact Sheet 17; Wikipedia).