Maryland Route 97 partially coincident with Maryland Route 140
In 1956, MD 97 was extended north to PA 16 at the Pennsylvania border northwest of Emmitsburg, Frederick County. The route ran north from Cooksville to Fenby, replacing both sections of MD 570, before it replaced MD 32 from Fenby north to Westminster and northwest through Taneytown and Emmitsburg. In 1960, MD 97 was moved to a new alignment that bypassed Westminster along newly constructed New Washington Road between Fenby and US 140 and the Westminster Bypass to the northwest side of the city. MD 32 was designated onto the former alignment of MD 97 that passed through Westminster on Washington Road and Main Street. In 1961, MD 97 was shifted to a new alignment to the east between MD 26 and MD 32; the former alignment became MD 854. The intersection with MD 26 was replaced with an interchange in 1962. In 1964, construction began on a new alignment of MD 97 slightly to the north between Westminster and Taneytown. This alignment was completed in 1965, and the former alignment became a part of MD 32 (now MD 832). In 1966, the divided highway portion of MD 97 was extended north from Glenmont to MD 28 in Norbeck.In 1977, plans were made for US 140 to be decommissioned, with MD 97 to replace the section between Westminster and the Pennsylvania border, where it would connect to PA 97. This proposal was made in order to eliminate short routes from the U.S. Highway System. The American Association of State Highway and Transportation Officials approved the removal of the US 140 designation on October 28, 1977. On January 1, 1979, MD 97 was rerouted at Westminster to head north to the Pennsylvania border, replacing US 140. At the Pennsylvania border, the route connected to PA 97, which replaced the US 140 designation in Pennsylvania. Meanwhile, the former alignment of MD 97 between Westminster and the Pennsylvania border northwest of Emmitsburg became a part of MD 140. Dualization of MD 97 in Montgomery County was extended further north from MD 28 to MD 108 by 1989. An interchange was built with MD 200 (Intercounty Connector) north of MD 28, opening on February 23, 2011. An interchange was built at the route’s intersection with Randolph Road in order to improve movements for automobiles as well as for pedestrians and bicycles accessing the nearby Glenmont Metro station. Construction of the interchange at Randolph Road began in 2014 and was completed in 2018.On September 25, 2018, a groundbreaking was held for a $47.6 million project to build a relocated MD 97 around Brookeville, with Governor Larry Hogan in attendance. The relocated MD 97 will be a two-lane road that will bypass the section through the center of Brookeville. The route was being realigned to improve safety and traffic flow, as the alignment of the route in Brookeville has a sharp turn and a steep hill.  In 2022, the relocated MD 97 around Brookeville was expected to open in the middle part of 2023. The relocated MD 97 opened on May 21, 2023.
partially overlapping with partially intersecting with partially sharing with partially matching with partially aligning with