The original section of MD 24, which began at MD 23 in Forest Hill and included MD 165 through Pylesville, was constructed in the late 1910s and early 1920s. MD 24 was moved to the highway to Fawn Grove after that road was built in the late 1920s and early 1930s. The highway between US 1 in Bel Air and US 40 in Edgewood was also constructed in the late 1920s and early 1930s. The state highway from US 40 south to Aberdeen Proving Ground was constructed as MD 408 around 1930. After the road from Bel Air to Forest Hill was completed in the mid-1930s, MD 24 was extended south to Edgewood.