A second, disconnected segment of MD 135 was constructed in two sections between MD 38 in Altamont and Swanton that were completed in 1933 and 1935. This road was extended east to the top of Backbone Mountain in 1939. The discontinuous segments of MD 135 were unified in 1953 when the pre-existing Bloomington Road was reconstructed between the eastern end of the western MD 135 on top of Backbone Mountain and the western end of the eastern MD 135 in Bloomington. When the present US 220 bridge over the Potomac River was completed in 1951, MD 135 was extended east from its old intersection with US 220, which is today the intersection with MD 135A, to its present eastern terminus.