cloverleaf interchange with I-495 (Capital Beltway) that includes access to Cabin John Parkway. East of the Capital Beltway, the route becomes a partially controlled access highway, with adjacent properties accessed by service roads or intersecting streets. MD 190 passes to the south of the Burning Tree Club and the Holton-Arms School before crossing Booze Creek. The highway continues through the southern part of Bethesda, where the road intersects MD 188 (Wilson Lane) and MD 614 (Goldsboro Road); between the two highways, the highway passes south of Walt Whitman High School. 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. The highway becomes an undivided four-lane road between its intersection with Little Falls Parkway and its crossing of Little Falls Branch. MD 190 reaches its eastern terminus at Western Avenue at the District of Columbia boundary. River Road continues into Washington, D.C. as a two-lane unnumbered street that ends at Wisconsin Avenue in Tenleytown. MD 190 is a part of the National Highway System as a principal arterial from MD 189 in Potomac to its eastern terminus. History 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. Montgomery County applied for state aid for the road by 1910; it was built as a macadam road by 1915. A second section of macadam road was built from Bradley Lane to a point just west of Potomac by 1923. The western section was extended as a concrete road from Potomac to near Piney Meetinghouse Road in 1925 and 1926. A third segment of MD 190 was built as a concrete road from Cabin John Creek to Booze Creek in 1928. The original extent of the state highway was finished when the gaps in the highway between Bradley Lane and Wilson Lane were filled with macadam roadway by 1930. MD 190 was extended west from Piney Meetinghouse Road to Travilah Road, which was then MD 421, in 1950. River Road from MD 421 to MD 112 was completely reconstructed as a federal aid project for Montgomery County between 1954 and 1956. This improved road was brought into the state system as the westernmost portion of MD 190 in 1974. MD 190 was expanded to a four-lane divided highway from just west of