MD 63 and MD 68 expand to a four-lane divided highway through their interchange with I-81 (Maryland Veterans Memorial Highway). A park and ride lot is located within the northwest quadrant of this interchange. At the northern end of the interchange, the state highways enter the town of Williamsport, where the highways follow municipally-maintained Conococheague Street through the Williamsport Historic District. In the center of town, the two highways meet US 11 (Potomac Street). MD 68 continues north while MD 63 turns east onto Potomac Street to join US 11 in a short concurrency. MD 63 leaves US 11 by turning north onto Artizan Street. At the north town limit of Williamsport, state maintenance resumes and MD 63's name changes to Greencastle Pike. The old alignment of MD 63, Honeyfield Road, parallels the state highway on the west as the highway enters a mix of farmland, forest, and industrial properties and crosses over Semple Run and CSX's Lurgan Subdivision. MD 63 crosses a tributary of Conococheague Creek and expands to a four-lane divided highway through its interchange with I-70 (Eisenhower Memorial Highway).