Interstate 70 in Maryland

Interstate 70 (I-70) is a part of the Interstate Highway System that runs from Cove Fort, Utah, to Woodlawn just outside of Baltimore, Maryland. In Maryland, the Interstate Highway runs 91.85 miles (147.82 km) from the Pennsylvania state line in Hancock east to the Interstate's eastern terminus at its junction with I-695. I-70 is the primary east–west Interstate in Maryland; the Interstate Highway connects Baltimore—and Washington, D.C., via I-270—with Western Maryland. The Interstate serves Frederick and Hagerstown directly and provides access to Cumberland via its junction with I-68 at Hancock. I-70 runs concurrently with its predecessor highway, U.S. Route 40 (US 40), from Hancock to Indian Springs in Washington County and from Frederick to West Friendship in Howard County.

I-70's route from Frederick to West Friendship was constructed as a divided highway relocation of US 40 in the early to mid-1950s and a freeway bypass of Frederick in the late 1950s. The first section of the Interstate to be marked as I-70 was an upgrade of US 40 near Hancock in the early 1960s. The remainder of the Interstate highway in Maryland west of Frederick was built on a new alignment in the mid- to late 1960s. I-70 was constructed from West Friendship to its present terminus in Baltimore in the late 1960s. The highway from Bartonsville in Frederick County to West Friendship was upgraded to Interstate standards in the mid-1970s. The final non-limited access portion of I-70 between Frederick and Bartonsville was eliminated in the mid-1980s. The Interstate has been upgraded through Frederick in a series of projects that began in the late 1990s.^{[citation needed]}

I-70 was intended to enter Baltimore as an east–west freeway that had been proposed since the 1940s. Around 1960, I-70 was planned passing through a pair of parks and several neighborhoods in West Baltimore to end at an interchange with I-95 and I-83 at the Inner Harbor in Downtown Baltimore. A subsequent proposal based on a review of the 1960 plan moved I-70 to a new alignment that triggered community opposition, which resulted in a new design process in the late 1960s. A new plan was introduced around 1970 that would have moved I-70's eastern terminus to Sowebo (South West Baltimore). Community opposition to the Interstate's planned route through the city parks, however, resulted in I-70 being removed from city plans in the early 1980s.^{[citation needed]}

I-70 has several official designations along its course through Maryland. The Interstate Highway is designated Eisenhower Memorial Highway from the Pennsylvania state line east to I-270 in Frederick. The highway received this designation from a 1973 act of Congress commemorating the route of the 1919 U.S. Army convoy from Washington, D.C., to San Francisco, California, in which President Dwight D. Eisenhower participated, an ordeal that served as one of his inspirations for the Interstate Highway System. All of I-70 in Frederick County was designated the Korean War Veterans Memorial Highway by the Maryland General Assembly in 2002. Large stone markers featuring reliefs of the Korean Peninsula were erected in the median of I-70 in Myersville and Mount Airy in 2004. Along its concurrency with US 40 from I-270 in Frederick to east of West Friendship, I-70 is known as Baltimore National Pike. The Interstate is unnamed from US 40 near West Friendship to its eastern terminus in Baltimore. Like all mainline Interstates, I-70 is a part of the National Highway System for its entire length.

I-70 enters Washington County concurrent with US 522 from Fulton County, Pennsylvania, north of the town of Hancock. Just south of the state line, the four-lane freeway has a full Y interchange with I-68 and US 40, which head west toward Cumberland as the National Freeway. US 40 begins to run concurrently with I-70 just as US 522 leaves I-70 at another full Y interchange through which I-70 curves to the east. US 522 heads south, providing access to downtown Hancock before crossing the Potomac River into West Virginia. I-70 heads east and gains a lane in each direction to climb a ridge that separates the interchanges from the valley of Tonoloway Creek. The third lane eastbound ends at the top of the ridge and the third lane westbound begins just west of the Interstate's partial interchange with Maryland Route 144 (MD 144; Main Street), which lacks a ramp from MD 144 to westbound I-70.

East of MD 144, I-70 parallels the Western Maryland Rail Trail, Chesapeake and Ohio Canal, and Potomac River while heading east along a narrow corridor between the river and several north–south ridges. Within this corridor, the freeway has a pair of partial interchanges with MD 615 (Millstone Road). West of Indian Springs, the valley opens up, and US 40 leaves the Interstate at a partial interchange just west of Licking Creek. I-70 continues to parallel the canal and rail trail at a distance until its diamond interchange with MD 56 (Big Pool Road) at Big Pool, where the freeway curves away from the Potomac River and passes to the south of Stone Quarry Ridge and Boyd Mountain. Just south of Clear Spring, I-70 crosses Toms Run within its diamond interchange with MD 68 (Clear Spring Road). Signs on westbound I-70 prior to the MD 68 interchange remind motorists they should remain on I-70 to access I-68.

I-70 continues east through Hagerstown Valley, where the highway crosses over Little Conococheague, Meadow Brook, and Conococheague creeks before reaching a diamond interchange with MD 63 (Greencastle Pike) south of Huyett. As the Interstate approaches Hagerstown, it crosses a branch of Conococheague Creek and CSX Transportation's Lurgan Subdivision ahead of its cloverleaf interchange with I-81 (Maryland Veterans Memorial Highway). I-70 heads southeast through the interchange, which has collector/distributor lanes in both directions that separate the individual ramps from the main roadways of both Interstates. The freeway traverses US 11 (Virginia Avenue) and the Winchester and Western Railroad before it curves to the east again. The Interstate has partial cloverleaf interchanges with MD 632 (Downsville Pike) and MD 65 (Sharpsburg Pike) around a crossing of Norfolk Southern Railway's Hagerstown District rail line. I-70 crosses over Antietam Creek and US 40 Alternate (US 40 Alt., Boonsboro Pike) south of Funkstown.

I-70 meets US 40 (National Pike) at a cloverleaf interchange as the two highways leave the suburban area surrounding Hagerstown. The Interstate curves to the southeast and has a diamond interchange with MD 66 (Mapleville Road) near Beaver Creek. I-70 crosses Beaver and Black Rock creeks and gains an eastbound climbing lane as the highway ascends South Mountain and passes through Greenbrier State Park. At the top of the mountain, the Interstate passes under US 40 and the Appalachian Trail and enters Frederick County. I-70 has a pair of rest areas on the east side of the mountain, one per direction. The westbound rest area is where the DC snipers, John Allen Muhammad and Lee Boyd Malvo, were apprehended by police in October 2002.