The first segment of MD 198 was built as a concrete road from US 1 west to Contee Road by 1921; the two roads intersected at the site of the modern I-95 interchange. The concrete road was extended west to the Montgomery–Prince George's county line in 1923. In Laurel, MD 198 originally followed Montgomery Street and the piece of Sandy Spring Road north of modern MD 198 from Montgomery Street to the I-95 interchange. A separate segment of MD 198 was built as a macadam road from MD 27 (later US 29, now MD 650) to a point east of Good Hope Road in 1929 and 1930. In addition, the first segment of the state highway was extended as a macadam road from the county line to the western Old Columbia Pike intersection in Burtonsville; the macadam road continued south along Old Columbia Pike, which was then designated MD 196. MD 198 was widened with a pair of bituminous shoulders from the county line east to Laurel between 1938 and 1940. There remained a gap in MD 198 between Spencerville and Burtonsville until the intervening county road was brought into state maintenance in 1956.