MD 225 begins at an intersection with MD 210 in Potomac Heights. The state highway heads south as a two-lane undivided road, descending into the forested bottomlands of Mattawoman Creek, where the highway intersects the Indian Head Rail Trail and intersects MD 224. The two highways join in a concurrency to cross the creek into the hamlet of Mason Springs, where MD 224 diverges to the west toward Marbury and MD 225 passes the historic home Araby. MD 225 heads southeast along the southern edge of Myrtle Grove Wildlife Management Area to the community of Ripley, where the highway curves east. At the hamlet of Marshalls Corner, the state highway intersects Marshall Corner Road, which heads north to Pomfret, and Rose Hill Road, which provides access to Thomas Stone National Historic Site. MD 225 passes the historic home Locust Grove before intersecting Valley Road and Mitchell Road at the corner of the Hawthorne Country Club. Valley Road heads north toward a trio of historic homes—Linden, Mount Carmel Monastery, and Thainston— and the La Plata campus of the College of Southern Maryland. MD 225 enters the town of La Plata, passing through a residential area before heading south of a park and ride lot and reaching its eastern terminus at US 301. The roadway continues east as Hawthorne Drive, the old alignment of MD 225, east to Washington Avenue, the old alignment of US 301. MD 225 is a part of the National Highway System as a principal arterial from Quailwood Parkway just west of the town of La Plata east to US 301 in La Plata.
History
The La Plata-Indian Head road was one of the original state roads marked for improvement by the Maryland State Roads Commission in 1909. A short section of pavement had already been laid as a state aid road in Potomac Heights by 1910. The highway was constructed as a gravel road from Indian Head to Mason Springs in 1913 and from La Plata to Ripley in 1915. The gap between Mason Springs and Ripley was filled by 1919. In La Plata, the highway's eastern terminus was originally Washington Avenue, which was the original alignment of MD 3 and later US 301. MD 225 originally extended west along Strauss Avenue through Indian Head to the entrance to U.S. Naval Proving Ground. The state highway was supplanted by Indian Head Highway as the main access to the military base when that highway was constructed from Washington to Indian Head during World War II. MD 225 was relocated from Strauss Avenue to its present terminus western terminus in Potomac Heights in 1950. The state highway was widened to a road with a bituminous-stabilized gravel surface from La Plata to Ripley in 1949 and 1950 and from Ripley to Potomac Heights in 1951. MD 225 was resurfaced again in 1953 and 1954. MD 225's eastern terminus was rolled back from Washington Avenue to US 301 around 1956.
