 The two sections of MD 23 are connected by a short concurrency with MD 165.MD 23 from Hickory to Jarrettsville was one of the original state highways marked for improvement by the Maryland State Roads Commission in 1909 and one of the original state-numbered highways in 1927.The state road was constructed from Hickory to Jarrettsville and from Norrisville to the state line in the early to mid-1910s.