Known as Wilson Lane, the highway runs 3.25 miles (5.23 km) from MacArthur Boulevard near Glen Echo east to MD 187 in Bethesda in Montgomery County.

MD 188 begins at MacArthur Boulevard just north of the town of Glen Echo and just east of the Union Arch Bridge, which the county-maintained highway uses to cross the deep valley of Cabin John Creek.

The highway heads northeast as a two-lane undivided road between affluent residential neighborhoods in the western part of Bethesda.

The highway is flanked on its eastbound side by a service road as it passes south of the Landon School.

[3] The highway was built as a 14-foot-wide (4.3 m) macadam road from the Woodmont area of Bethesda west to Glen Echo by 1915.