The state highway heads east as Ridge Road, which follows the height of land between the Upper Machodic Creek watershed to the north and Pine Hill Creek to the south.

SR 205 intersects U.S. Route 301 (James Madison Parkway) at Edgehill and passes through Carruthers Corner and Alden.

The state highway continues through Ninde before it descends from the ridge to meet the eastern end of SR 218 (Tetotum Road) south of Tetotum just before crossing Pine Hill Creek into Westmoreland County.

[1][2] SR 205 curves northeast to approach the Potomac River shoreline, where the highway crosses Goldman Creek into the town of Colonial Beach.

SR 205Y, which has a length of 0.71 miles (1.14 km), serves as the main street of the town and has its eastern terminus at the town's beach terrace about 150 feet (46 m) west of the Virginia–Maryland state line, which follows the low water mark of the south shore of the Potomac River.