Maryland Route 68 (MD 68) is a state highway in the U.S. state of Maryland. The state highway runs 18.50 miles (29.77 km) from U.S. Route 40 (US 40) in Clear Spring east to US 40 Alternate in Boonsboro. MD 68 crosses central Washington County to the south of Hagerstown, connecting Clear Spring and Boonsboro with Williamsport, where the highway runs concurrently with MD 63. A small segment of MD 68 west of Boonsboro was constructed around 1920, using as part of the route two early 19th-century stone bridges. The remainder of the highway between Boonsboro and Williamsport was constructed in the second half of the 1920s. MD 68 was extended west from Williamsport to Clear Spring in the mid-1950s. The state highway was relocated south of Williamsport for the construction of Interstate 81 (I-81) in the mid-1960s. Since the early 1990s, I-68 has also existed in Washington County; signs on I-70 aim to avoid confusion between I-68 and MD 68.
MD 68 begins at an intersection with US 40 (Cumberland Street) in the town of Clear Spring. The state highway heads south as Mill Street through a commercial area. MD 68's name changes to Clear Spring Road after leaving the town limits. The state highway meets I-70 (Eisenhower Memorial Highway) at a diamond interchange, then heads southeast through farmland, where the highway crosses Little Conococheague Creek. MD 68 intersects the eastern end of MD 56 (Big Pool Road) shortly before passing through the village of Pinesburg. The state highway intersects CSX's Lurgan Subdivision rail line and passes between industrial properties, then crosses Conococheague Creek and enters the town of Williamsport. MD 68 is municipally maintained within the town, where the highway follows Conococheague Street south through an intersection with US 11 (Potomac Street). At this intersection, MD 63 joins MD 68 in a concurrency to continue through the Williamsport Historic District. The two highways leave the town limits at their diamond interchange with I-81 (Maryland Veterans Memorial Highway), through which the roadway temporarily expands to a four-lane divided highway. A park and ride lot is located within the northwest quadrant of this interchange.
MD 68's name changes to Lappans Road south of Williamsport. MD 63 (Spielman Road) splits south from MD 68 at the same intersection as Governor Lane Boulevard, which serves an industrial park. MD 68 crosses over the Winchester and Western Railroad and curves to the east, then resumes heading southeast after intersecting the eastern end of Kendle Road. The state highway heads southeast through farmland and intersects MD 632 (Downsville Pike). The road intersects Norfolk Southern Railway's Hagerstown District at-grade and crosses St. James Run in the hamlet of St. James. MD 68 intersects MD 65 (Sharpsburg Pike) in the hamlet of Lappans, where the highway passes St. Mark's Episcopal Church. The state highway passes through the hamlet of Brethedsville and passes Devils Backbone County Park as the highway follows Antietam Creek for a short distance. MD 68 crosses over the creek on a narrow stone bridge, then makes a sharp turn to the south to continue following the forested valley of the creek. The state highway crosses over Beaver Creek on a one-lane stone bridge before leaving the creek valley. MD 68 continues southeast through farmland and the hamlet of Millpoint before reaching its eastern terminus at US 40 Alternate (Main Street) on the northern edge of the town of Boonsboro.
The first section of MD 68, from Lappans to Millpoint near Boonsboro, was constructed in 1920. This segment made use of a pair of stone arch bridges over Antietam Creek and Beaver Creek constructed in 1833 and 1824, respectively. These bridges remain open to traffic as part of MD 68. MD 68 was extended east from Millpoint to Boonsboro in 1925. Construction of MD 68 from Williamsport to Lappans began in 1926, with a section complete from Williamsport to the Cumberland Valley Railroad (now Winchester and Western Railroad) by 1927. The last section of the Williamsport–Lappans Road was completed in 1930. The state highway's western terminus was originally US 11 in Williamsport, within which MD 68 followed Artizan Street south to Sunset Avenue at the southern town limit. Artizan Street continued south as MD 63 and MD 68 followed Sunset Avenue southeast toward Lappans. Clear Spring Road remained a county highway until MD 68 was extended west to Clear Spring in 1956.