Known as River Road, the highway runs 15.88 miles (25.56 km) from MD 112 near Seneca east to Western Avenue at the District of Columbia boundary in Bethesda.

The westernmost 8.14 miles (13.10 km) of MD 190 are signed concurrently with the Chesapeake and Ohio Canal Scenic Byway, a state tourist route.

The road intersects several county highways that provide access to the Chesapeake and Ohio Canal National Historical Park.

MD 190 crosses Watts Branch west of Piney Meetinghouse Road, where the Potomac River curves south away from the highway.

[1][3] MD 190 crosses Cabin John Creek and expands to a four-lane divided highway just west of Seven Locks Road.

The state highway has a partial cloverleaf interchange with I-495 (Capital Beltway) that includes access to Cabin John Parkway.

MD 190 loses access of control and becomes an undivided road with a center left-turn lane west of its underpass of the Capital Crescent Trail.

[1][4] The first section of River Road to be paved was from the District of Columbia boundary west to Wilson Lane at the hamlet of Cohasset.