US 140 began at the intersection of US 1 (North Avenue) and Pennsylvania Avenue in Baltimore. Pennsylvania Avenue continues southeast from the intersection and would have connected US 140 with US 40, which then followed Franklin Street through downtown Baltimore. US 140 headed northeast on Pennsylvania Avenue three blocks to Fulton Street, where the U.S. Highway joined Reisterstown Road at its southern end. US 140 intersected Gwynns Falls Parkway and MD 26 (Liberty Heights Avenue), which were both boulevards. US 140 itself became a divided highway and passed along the edge of Druid Hill Park to Park Circle, which was then a traffic circle, where the highway met the southern end of MD 129 (Park Heights Avenue) and also Druid Park Drive. From Park Circle, US 140 became an undivided street that followed MD 140's out of the city of Baltimore.