Howard Johnson Road was constructed as a county highway between MD 291 and Millington Road after US 301 was built through the Millington area between 1954 and 1957. The 0.71-mile-long (1.14 km) highway was brought into state maintenance through a December 1, 1987, road transfer agreement and designated MD 701 in July 1988. Less than a decade later, the state and county signed a November 25, 1997, road transfer agreement through which the state would turn over the portions of MD 701 and the proposed service road on the west side of US 301, MD 701A, to the county after the service roads were reconstructed and resurfaced and the US 301–MD 291 interchange was completed. The interchange was constructed in 1998 and 1999. The portion of MD 701 south from the interchange ramps was relocated during the interchange construction. In 1999, MD 701 north of the interchange ramps was transferred to state maintenance, and MD 701A was assigned to its present length along Edge Road. In addition, Chesterville Bridge Road and Millington Road, which had previously had a normal intersection with US 301, were separated into separate county highways when the median of US 301 was closed. Access between the county highways requires using both MD 701s and their county extensions to cross over US 301 on MD 291.
Maryland Route 703 is the unsigned designation for a 0.08 mi (0.13 km) L-shaped spur near Goodwill, part of an old alignment of MD 366, that runs east from a dead end to county-maintained Klej Grange Road, then turns right to connect that road with current MD 366.