Known as Hawthorne Road, the state highway runs 10.59 miles (17.04 km) from MD 210 in Potomac Heights east to U.S. Route 301 (US 301) in La Plata.

The state highway heads south as a two-lane undivided road, descending into the forested bottomlands of Mattawoman Creek, where the highway crosses the Indian Head Rail Trail and intersects MD 224 (Livingston Road).

MD 225 heads southeast along the southern edge of Myrtle Grove Wildlife Management Area to the community of Ripley, where the highway curves east.

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.

[4] The highway was constructed as a 14-foot (4.3 m) gravel road from Indian Head to Mason Springs in 1913 and from La Plata to Ripley in 1915.